diff --git a/src/main/java/com/potatocake/everymoment/controller/CommentController.java b/src/main/java/com/potatocake/everymoment/controller/CommentController.java
new file mode 100644
index 0000000..f462e1d
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/controller/CommentController.java
@@ -0,0 +1,51 @@
+package com.potatocake.everymoment.controller;
+
+import com.potatocake.everymoment.dto.SuccessResponse;
+import com.potatocake.everymoment.dto.request.CommentRequest;
+import com.potatocake.everymoment.security.MemberDetails;
+import com.potatocake.everymoment.service.CommentService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RequiredArgsConstructor
+@RestController
+@RequestMapping("/api/comments")
+public class CommentController {
+
+    private final CommentService commentService;
+
+    //댓글 수정
+    @PatchMapping("/{commentId}")
+    public ResponseEntity<SuccessResponse<Void>> updateComment(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long commentId,
+            @RequestBody CommentRequest commentRequest) {
+        Long memberId = memberDetails.getId();
+
+        commentService.updateComment(memberId, commentId, commentRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
+    }
+
+    //댓글 삭제
+    @DeleteMapping("/{commentId}")
+    public ResponseEntity<SuccessResponse<Void>> deleteComment(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long commentId) {
+        Long memberId = memberDetails.getId();
+
+        commentService.deleteComment(memberId, commentId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
+    }
+}
diff --git a/src/main/java/com/potatocake/everymoment/controller/DiaryController.java b/src/main/java/com/potatocake/everymoment/controller/DiaryController.java
index e149daa..66047a9 100644
--- a/src/main/java/com/potatocake/everymoment/controller/DiaryController.java
+++ b/src/main/java/com/potatocake/everymoment/controller/DiaryController.java
@@ -1,14 +1,19 @@
 package com.potatocake.everymoment.controller;
 
 import com.potatocake.everymoment.dto.SuccessResponse;
+import com.potatocake.everymoment.dto.request.CommentRequest;
 import com.potatocake.everymoment.dto.request.DiaryAutoCreateRequest;
 import com.potatocake.everymoment.dto.request.DiaryFilterRequest;
 import com.potatocake.everymoment.dto.request.DiaryManualCreateRequest;
+import com.potatocake.everymoment.dto.response.CommentsResponse;
 import com.potatocake.everymoment.dto.response.FriendDiariesResponse;
 import com.potatocake.everymoment.dto.response.FriendDiaryResponse;
+import com.potatocake.everymoment.dto.response.MemberDetailResponse;
 import com.potatocake.everymoment.dto.response.MyDiariesResponse;
 import com.potatocake.everymoment.dto.response.MyDiaryResponse;
 import com.potatocake.everymoment.dto.response.NotificationResponse;
+import com.potatocake.everymoment.security.MemberDetails;
+import com.potatocake.everymoment.service.CommentService;
 import com.potatocake.everymoment.service.DiaryService;
 import com.potatocake.everymoment.service.FriendDiaryService;
 import java.time.LocalDate;
@@ -16,6 +21,7 @@
 import org.springframework.format.annotation.DateTimeFormat;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PatchMapping;
@@ -33,36 +39,37 @@ public class DiaryController {
 
     private final DiaryService diaryService;
     private final FriendDiaryService friendDiaryService;
+    private final CommentService commentService;
 
     //자동 일기 작성
     @PostMapping("/auto")
     public ResponseEntity<SuccessResponse<NotificationResponse>> createDiaryAuto(
+            @AuthenticationPrincipal MemberDetails memberDetails,
             @RequestBody DiaryAutoCreateRequest diaryAutoCreateRequest) {
-        NotificationResponse notificationResponse = diaryService.createDiaryAuto(diaryAutoCreateRequest);
-        SuccessResponse<NotificationResponse> response = SuccessResponse.<NotificationResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(notificationResponse)
-                .build();
-        return ResponseEntity.ok(response);
+        Long memberId = memberDetails.getId();
+
+        NotificationResponse response = diaryService.createDiaryAuto(memberId, diaryAutoCreateRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //수기 일기 작성
     @PostMapping("/manual")
     public ResponseEntity<SuccessResponse<Void>> createDiaryManual(
+            @AuthenticationPrincipal MemberDetails memberDetails,
             @RequestBody DiaryManualCreateRequest diaryManualCreateRequest) {
-        diaryService.createDiaryManual(diaryManualCreateRequest);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+        Long memberId = memberDetails.getId();
+        diaryService.createDiaryManual(memberId, diaryManualCreateRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //내 일기 전체 조회(타임라인)
     @GetMapping("/my")
     public ResponseEntity<SuccessResponse<MyDiariesResponse>> getMyDiaries(
+            @AuthenticationPrincipal MemberDetails memberDetails,
             @RequestParam(required = false) String keyword,
             @RequestParam(required = false) String emoji,
             @RequestParam(required = false) Long category,
@@ -73,6 +80,7 @@ public ResponseEntity<SuccessResponse<MyDiariesResponse>> getMyDiaries(
             @RequestParam(defaultValue = "0") int key,
             @RequestParam(defaultValue = "10") int size
     ) {
+        Long memberId = memberDetails.getId();
         DiaryFilterRequest diaryFilterRequest = DiaryFilterRequest.builder()
                 .keyword(keyword)
                 .emoji(emoji)
@@ -85,79 +93,82 @@ public ResponseEntity<SuccessResponse<MyDiariesResponse>> getMyDiaries(
                 .size(size)
                 .build();
 
-        MyDiariesResponse myDiariesResponse = diaryService.getMyDiaries(diaryFilterRequest);
-        SuccessResponse<MyDiariesResponse> response = SuccessResponse.<MyDiariesResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(myDiariesResponse)
-                .build();
-        return ResponseEntity.ok(response);
+        MyDiariesResponse response = diaryService.getMyDiaries(memberId, diaryFilterRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //내 일기 상세 조회
-    @GetMapping("/my/{id}")
-    public ResponseEntity<SuccessResponse<MyDiaryResponse>> getMyDiary(@PathVariable Long id) {
-        MyDiaryResponse myDiaryResponse = diaryService.getMyDiary(id);
-        SuccessResponse<MyDiaryResponse> response = SuccessResponse.<MyDiaryResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(myDiaryResponse)
-                .build();
-        return ResponseEntity.ok(response);
+    @GetMapping("/my/{diaryId}")
+    public ResponseEntity<SuccessResponse<MyDiaryResponse>> getMyDiary(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId) {
+        Long memberId = memberDetails.getId();
+
+        MyDiaryResponse response = diaryService.getMyDiary(memberId, diaryId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //일기 수정
-    @PatchMapping("/{id}")
-    public ResponseEntity<SuccessResponse<Void>> updateDiary(@PathVariable Long id,
-                                                             @RequestBody DiaryManualCreateRequest diaryManualCreateRequest) {
-        diaryService.updateDiary(id, diaryManualCreateRequest);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @PatchMapping("/{diaryId}")
+    public ResponseEntity<SuccessResponse<Void>> updateDiary(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId,
+            @RequestBody DiaryManualCreateRequest diaryManualCreateRequest) {
+        Long memberId = memberDetails.getId();
+
+        diaryService.updateDiary(memberId, diaryId, diaryManualCreateRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //일기 삭제
-    @DeleteMapping("/{id}")
-    public ResponseEntity<SuccessResponse<Void>> deleteDiary(@PathVariable Long id) {
-        diaryService.deleteDiary(id);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @DeleteMapping("/{diaryId}")
+    public ResponseEntity<SuccessResponse<Void>> deleteDiary(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId) {
+        Long memberId = memberDetails.getId();
+
+        diaryService.deleteDiary(memberId, diaryId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //북마크 설정 토글
-    @PatchMapping("/{id}/bookmark")
-    public ResponseEntity<SuccessResponse<Void>> toggleBookmark(@PathVariable Long id) {
-        diaryService.toggleBookmark(id);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @PatchMapping("/{diaryId}/bookmark")
+    public ResponseEntity<SuccessResponse<Void>> toggleBookmark(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId) {
+        Long memberId = memberDetails.getId();
+
+        diaryService.toggleBookmark(memberId, diaryId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //공개 설정 토글
-    @PatchMapping("/{id}/privacy")
-    public ResponseEntity<SuccessResponse<Void>> togglePrivacy(@PathVariable Long id) {
-        diaryService.togglePrivacy(id);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @PatchMapping("/{diaryId}/privacy")
+    public ResponseEntity<SuccessResponse<Void>> togglePrivacy(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId) {
+        Long memberId = memberDetails.getId();
+
+        diaryService.togglePrivacy(memberId, diaryId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //전체 친구 일기 조회
     @GetMapping("/friend")
     public ResponseEntity<SuccessResponse<FriendDiariesResponse>> getFriendDiaries(
+            @AuthenticationPrincipal MemberDetails memberDetails,
             @RequestParam(required = false) String keyword,
             @RequestParam(required = false) String emoji,
             @RequestParam(required = false) Long category,
@@ -168,6 +179,7 @@ public ResponseEntity<SuccessResponse<FriendDiariesResponse>> getFriendDiaries(
             @RequestParam(defaultValue = "0") int key,
             @RequestParam(defaultValue = "10") int size
     ) {
+        Long memberId = memberDetails.getId();
         DiaryFilterRequest diaryFilterRequest = DiaryFilterRequest.builder()
                 .keyword(keyword)
                 .emoji(emoji)
@@ -180,24 +192,49 @@ public ResponseEntity<SuccessResponse<FriendDiariesResponse>> getFriendDiaries(
                 .size(size)
                 .build();
 
-        FriendDiariesResponse diaries = friendDiaryService.getFriendDiaries(diaryFilterRequest);
-        SuccessResponse<FriendDiariesResponse> response = SuccessResponse.<FriendDiariesResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(diaries)
-                .build();
-        return ResponseEntity.ok(response);
+        FriendDiariesResponse response = friendDiaryService.getFriendDiaries(memberId, diaryFilterRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //친구 일기 상제 조회
-    @GetMapping("/friend/{id}")
-    public ResponseEntity<SuccessResponse<FriendDiaryResponse>> getFriendDiary(@PathVariable Long id) {
-        FriendDiaryResponse diary = friendDiaryService.getFriendDiary(id);
-        SuccessResponse<FriendDiaryResponse> response = SuccessResponse.<FriendDiaryResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(diary)
-                .build();
-        return ResponseEntity.ok(response);
+    @GetMapping("/friend/{diaryId}")
+    public ResponseEntity<SuccessResponse<FriendDiaryResponse>> getFriendDiary(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId) {
+        Long memberId = memberDetails.getId();
+
+        FriendDiaryResponse response = friendDiaryService.getFriendDiary(memberId, diaryId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
+    }
+
+    //댓글 조회
+    @GetMapping("/{diaryId}/comments")
+    public ResponseEntity<SuccessResponse<CommentsResponse>> getComments(
+            @PathVariable Long diaryId,
+            @RequestParam(defaultValue = "0") int key,
+            @RequestParam(defaultValue = "10") int size
+    ) {
+        CommentsResponse response = commentService.getComments(diaryId, key, size);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
+    }
+
+    //댓글 작성
+    @PostMapping("/{diaryId}/comments")
+    public ResponseEntity<SuccessResponse<Void>> createComment(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long diaryId,
+            @RequestBody CommentRequest commentRequest) {
+        Long memberId = memberDetails.getId();
+
+        commentService.createComment(memberId, diaryId, commentRequest);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 }
diff --git a/src/main/java/com/potatocake/everymoment/controller/FriendController.java b/src/main/java/com/potatocake/everymoment/controller/FriendController.java
index 8fb3f75..79772c9 100644
--- a/src/main/java/com/potatocake/everymoment/controller/FriendController.java
+++ b/src/main/java/com/potatocake/everymoment/controller/FriendController.java
@@ -3,11 +3,14 @@
 import com.potatocake.everymoment.dto.SuccessResponse;
 import com.potatocake.everymoment.dto.response.FriendListResponse;
 import com.potatocake.everymoment.dto.response.OneFriendDiariesResponse;
+import com.potatocake.everymoment.entity.Member;
+import com.potatocake.everymoment.security.MemberDetails;
 import com.potatocake.everymoment.service.FriendService;
 import java.time.LocalDate;
 import org.springframework.format.annotation.DateTimeFormat;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PatchMapping;
@@ -17,7 +20,7 @@
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
-@RequestMapping("api/friends")
+@RequestMapping("/api/friends")
 public class FriendController {
     private final FriendService friendService;
 
@@ -26,57 +29,59 @@ public FriendController(FriendService friendService) {
     }
 
     //특정 친구 일기 전체 조회
-    @GetMapping("/{id}/diaries")
+    @GetMapping("/{friendId}/diaries")
     public ResponseEntity<SuccessResponse<OneFriendDiariesResponse>> getOneFriendDiaries(
-            @PathVariable Long id,
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long friendId,
             @RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date,
             @RequestParam(defaultValue = "0") int key,
             @RequestParam(defaultValue = "10") int size) {
-        OneFriendDiariesResponse diaries = friendService.OneFriendDiariesResponse(id, date, key, size);
-        SuccessResponse<OneFriendDiariesResponse> response = SuccessResponse.<OneFriendDiariesResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(diaries)
-                .build();
-        return ResponseEntity.ok(response);
+        Long memberId = memberDetails.getId();
+
+        OneFriendDiariesResponse response = friendService.OneFriendDiariesResponse(memberId, friendId, date, key, size);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //내 친구 목록 조회
     @GetMapping("/friends")
     public ResponseEntity<SuccessResponse<FriendListResponse>> getFriendList(
+            @AuthenticationPrincipal MemberDetails memberDetails,
             @RequestParam(required = false) String nickname,
             @RequestParam(defaultValue = "0") int key,
             @RequestParam(defaultValue = "10") int size) {
-        FriendListResponse friendList = friendService.getFriendList(nickname, key, size);
-        SuccessResponse<FriendListResponse> response = SuccessResponse.<FriendListResponse>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(friendList)
-                .build();
-        return ResponseEntity.ok(response);
+        Long memberId = memberDetails.getId();
+
+        FriendListResponse response = friendService.getFriendList(memberId, nickname, key, size);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
     }
 
     //내 친구 삭제
-    @DeleteMapping("/{id}")
-    public ResponseEntity<SuccessResponse<Void>> deleteFriend(@PathVariable Long id) {
-        friendService.deleteFriend(id);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @DeleteMapping("/{friendId}")
+    public ResponseEntity<SuccessResponse<Void>> deleteFriend(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long friendId) {
+        Long memberId = memberDetails.getId();
+
+        friendService.deleteFriend(memberId, friendId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 
     //친한 친구 설정
-    @PatchMapping("/{id}/bookmark")
-    public ResponseEntity<SuccessResponse<Void>> toggleCloseFriend(@PathVariable Long id) {
-        friendService.toggleCloseFriend(id);
-        SuccessResponse<Void> response = SuccessResponse.<Void>builder()
-                .code(HttpStatus.OK.value())
-                .message("success")
-                .info(null)
-                .build();
-        return ResponseEntity.ok(response);
+    @PatchMapping("/{friendId}/bookmark")
+    public ResponseEntity<SuccessResponse<Void>> toggleCloseFriend(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long friendId) {
+        Long memberId = memberDetails.getId();
+
+        friendService.toggleCloseFriend(memberId, friendId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
     }
 }
diff --git a/src/main/java/com/potatocake/everymoment/controller/NotificationController.java b/src/main/java/com/potatocake/everymoment/controller/NotificationController.java
new file mode 100644
index 0000000..e8ce3d9
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/controller/NotificationController.java
@@ -0,0 +1,46 @@
+package com.potatocake.everymoment.controller;
+
+import com.potatocake.everymoment.dto.SuccessResponse;
+import com.potatocake.everymoment.dto.response.NotificationListResponse;
+import com.potatocake.everymoment.security.MemberDetails;
+import com.potatocake.everymoment.service.NotificationService;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RequiredArgsConstructor
+@RestController
+@RequestMapping("/api/notifications")
+public class NotificationController {
+
+    private final NotificationService notificationService;
+
+    @GetMapping
+    public ResponseEntity<SuccessResponse<List<NotificationListResponse>>> getNotifications(
+            @AuthenticationPrincipal MemberDetails memberDetails){
+        Long memberId = memberDetails.getId();
+
+        List<NotificationListResponse> response = notificationService.getNotifications(memberId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok(response));
+    }
+
+    @PatchMapping("/{notificationId}")
+    public ResponseEntity<SuccessResponse<Void>> updateNotification(
+            @AuthenticationPrincipal MemberDetails memberDetails,
+            @PathVariable Long notificationId) {
+        Long memberId = memberDetails.getId();
+
+        notificationService.updateNotification(memberId, notificationId);
+
+        return ResponseEntity.ok()
+                .body(SuccessResponse.ok());
+    }
+}
diff --git a/src/main/java/com/potatocake/everymoment/dto/request/CommentRequest.java b/src/main/java/com/potatocake/everymoment/dto/request/CommentRequest.java
new file mode 100644
index 0000000..db0252a
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/dto/request/CommentRequest.java
@@ -0,0 +1,8 @@
+package com.potatocake.everymoment.dto.request;
+
+import lombok.Getter;
+
+@Getter
+public class CommentRequest {
+    private String content;
+}
diff --git a/src/main/java/com/potatocake/everymoment/dto/response/CommentFriendResponse.java b/src/main/java/com/potatocake/everymoment/dto/response/CommentFriendResponse.java
new file mode 100644
index 0000000..b6f09fc
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/dto/response/CommentFriendResponse.java
@@ -0,0 +1,12 @@
+package com.potatocake.everymoment.dto.response;
+
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class CommentFriendResponse {
+    private Long id;
+    private String nickname;
+    private String profileImageUrl;
+}
diff --git a/src/main/java/com/potatocake/everymoment/dto/response/CommentResponse.java b/src/main/java/com/potatocake/everymoment/dto/response/CommentResponse.java
new file mode 100644
index 0000000..7fe835d
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/dto/response/CommentResponse.java
@@ -0,0 +1,14 @@
+package com.potatocake.everymoment.dto.response;
+
+import java.time.LocalDateTime;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class CommentResponse {
+    private Long id;
+    private CommentFriendResponse commentFriendResponse;
+    private String content;
+    private LocalDateTime createdAt;
+}
diff --git a/src/main/java/com/potatocake/everymoment/dto/response/CommentsResponse.java b/src/main/java/com/potatocake/everymoment/dto/response/CommentsResponse.java
new file mode 100644
index 0000000..160b79c
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/dto/response/CommentsResponse.java
@@ -0,0 +1,13 @@
+package com.potatocake.everymoment.dto.response;
+
+import java.util.List;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class CommentsResponse {
+    private List<CommentResponse> comments;
+    private Integer next;
+}
+
diff --git a/src/main/java/com/potatocake/everymoment/dto/response/NotificationListResponse.java b/src/main/java/com/potatocake/everymoment/dto/response/NotificationListResponse.java
new file mode 100644
index 0000000..f32770e
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/dto/response/NotificationListResponse.java
@@ -0,0 +1,17 @@
+package com.potatocake.everymoment.dto.response;
+
+import java.time.LocalDateTime;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class NotificationListResponse {
+    private Long id;
+    private String content;
+    private boolean isRead;
+    private String type;
+    private Long targetId;
+    private LocalDateTime createdAt;
+}
+
diff --git a/src/main/java/com/potatocake/everymoment/entity/Comment.java b/src/main/java/com/potatocake/everymoment/entity/Comment.java
new file mode 100644
index 0000000..5024398
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/entity/Comment.java
@@ -0,0 +1,43 @@
+package com.potatocake.everymoment.entity;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.Lob;
+import jakarta.persistence.ManyToOne;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+@Getter
+@Builder
+public class Comment extends BaseTimeEntity{
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(nullable = false)
+    private Member member;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(nullable = false)
+    private Diary diary;
+
+    @Lob
+    private String content;
+
+    public void updateContent(String content) {
+        if (content != null) {
+            this.content = content;
+        }
+    }
+}
diff --git a/src/main/java/com/potatocake/everymoment/entity/Diary.java b/src/main/java/com/potatocake/everymoment/entity/Diary.java
index a0ae427..a8abca1 100644
--- a/src/main/java/com/potatocake/everymoment/entity/Diary.java
+++ b/src/main/java/com/potatocake/everymoment/entity/Diary.java
@@ -27,7 +27,7 @@ public class Diary extends BaseTimeEntity {
 
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(nullable = false)
-    private Member memberId;
+    private Member member;
 
     @Lob
     private String content;
@@ -100,7 +100,7 @@ public void togglePublic() {
     }
 
     public boolean checkOwner(Long memberId) {
-        return this.memberId.getId().equals(memberId);
+        return this.member.getId().equals(memberId);
     }
 
 }
diff --git a/src/main/java/com/potatocake/everymoment/entity/Notification.java b/src/main/java/com/potatocake/everymoment/entity/Notification.java
index 7963a15..184ea96 100644
--- a/src/main/java/com/potatocake/everymoment/entity/Notification.java
+++ b/src/main/java/com/potatocake/everymoment/entity/Notification.java
@@ -27,7 +27,7 @@ public class Notification extends BaseTimeEntity {
 
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(nullable = false)
-    private Member memberId;
+    private Member member;
 
     @Column(nullable = false)
     private String content;
@@ -41,4 +41,8 @@ public class Notification extends BaseTimeEntity {
 
     @Column(nullable = false)
     private Long targetId;
+
+    public void updateIsRead() {
+        this.isRead = true;
+    }
 }
diff --git a/src/main/java/com/potatocake/everymoment/exception/ErrorCode.java b/src/main/java/com/potatocake/everymoment/exception/ErrorCode.java
index 365d29a..19b0d7c 100644
--- a/src/main/java/com/potatocake/everymoment/exception/ErrorCode.java
+++ b/src/main/java/com/potatocake/everymoment/exception/ErrorCode.java
@@ -23,6 +23,9 @@ public enum ErrorCode {
     /* Friend */
     FRIEND_NOT_FOUND("존재하지 않는 친구입니다.", NOT_FOUND),
 
+    /* Notification */
+    NOTIFICATION_NOT_FOUND("존재하지 않는 알림입니다.", NOT_FOUND),
+
     /* CategoryService */
     ALREADY_EXISTS_CATEGORY("이미 존재하는 카테고리입니다.", CONFLICT),
 
diff --git a/src/main/java/com/potatocake/everymoment/repository/CommentRepository.java b/src/main/java/com/potatocake/everymoment/repository/CommentRepository.java
new file mode 100644
index 0000000..8129c6d
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/repository/CommentRepository.java
@@ -0,0 +1,10 @@
+package com.potatocake.everymoment.repository;
+
+import com.potatocake.everymoment.entity.Comment;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+    Page<Comment> findAllByDiaryId(Long diaryId, Pageable pageable);
+}
diff --git a/src/main/java/com/potatocake/everymoment/repository/NotificationRepository.java b/src/main/java/com/potatocake/everymoment/repository/NotificationRepository.java
index a3a5974..19297a5 100644
--- a/src/main/java/com/potatocake/everymoment/repository/NotificationRepository.java
+++ b/src/main/java/com/potatocake/everymoment/repository/NotificationRepository.java
@@ -1,7 +1,9 @@
 package com.potatocake.everymoment.repository;
 
 import com.potatocake.everymoment.entity.Notification;
+import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface NotificationRepository extends JpaRepository<Notification, Long> {
+    List<Notification> findAllByMemberId(Long memberId);
 }
diff --git a/src/main/java/com/potatocake/everymoment/service/CommentService.java b/src/main/java/com/potatocake/everymoment/service/CommentService.java
new file mode 100644
index 0000000..b0d7663
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/service/CommentService.java
@@ -0,0 +1,117 @@
+package com.potatocake.everymoment.service;
+
+import com.potatocake.everymoment.dto.request.CommentRequest;
+import com.potatocake.everymoment.dto.response.CommentFriendResponse;
+import com.potatocake.everymoment.dto.response.CommentResponse;
+import com.potatocake.everymoment.dto.response.CommentsResponse;
+import com.potatocake.everymoment.entity.Comment;
+import com.potatocake.everymoment.entity.Diary;
+import com.potatocake.everymoment.entity.Member;
+import com.potatocake.everymoment.exception.ErrorCode;
+import com.potatocake.everymoment.exception.GlobalException;
+import com.potatocake.everymoment.repository.CommentRepository;
+import com.potatocake.everymoment.repository.DiaryRepository;
+import com.potatocake.everymoment.repository.MemberRepository;
+import com.potatocake.everymoment.security.MemberDetails;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@RequiredArgsConstructor
+@Transactional
+@Service
+public class CommentService {
+
+    private final CommentRepository commentRepository;
+    private final DiaryRepository diaryRepository;
+    private final MemberRepository memberRepository;
+
+    // 댓글 목록 조회
+    public CommentsResponse getComments(Long diaryId, int key, int size) {
+        Pageable pageable = PageRequest.of(key, size);
+        Page<Comment> commentPage = commentRepository.findAllByDiaryId(diaryId, pageable);
+
+        List<CommentResponse> commentResponses = commentPage.getContent().stream()
+                .map(this::convertToCommentResponseDTO)
+                .collect(Collectors.toList());
+
+        Integer nextKey = commentPage.hasNext() ? key + 1 : null;
+
+        return CommentsResponse.builder()
+                .comments(commentResponses)
+                .next(nextKey)
+                .build();
+    }
+
+    // 댓글 작성
+    public void createComment(Long memberId, Long diaryId, CommentRequest commentRequest) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+
+        Diary diary = diaryRepository.findById(diaryId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.DIARY_NOT_FOUND));
+
+        Comment comment = Comment.builder()
+                .content(commentRequest.getContent())
+                .member(currentMember)
+                .diary(diary)
+                .build();
+
+        commentRepository.save(comment);
+    }
+
+    // 댓글 수정
+    public void updateComment(Long memberId, Long commentId, CommentRequest commentRequest) {
+        Comment comment = getExistComment(memberId, commentId);
+        comment.updateContent(commentRequest.getContent());
+    }
+
+    // 댓글 삭제
+    public void deleteComment(Long memberId, Long commentId) {
+        Comment comment = getExistComment(memberId, commentId);
+        commentRepository.delete(comment);
+    }
+
+    // 로그인한 유저가 쓴 댓글인지 확인하고, 맞을시 댓글 반환
+    private Comment getExistComment(Long memberId, Long commentId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+
+        Comment comment = commentRepository.findById(commentId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.COMMENT_NOT_FOUND));
+
+        if(!Objects.equals(currentMember.getId(), comment.getMember().getId())){
+            throw new GlobalException(ErrorCode.COMMENT_NOT_FOUND);
+        }
+
+        return comment;
+    }
+
+    // 친구 프로필 DTO 변환
+    private CommentFriendResponse convertToCommentFriendResponseDTO(Member member){
+        return CommentFriendResponse.builder()
+                .id(member.getId())
+                .nickname(member.getNickname())
+                .profileImageUrl(member.getProfileImageUrl())
+                .build();
+    }
+
+    // 댓글 DTO 변환
+    private CommentResponse convertToCommentResponseDTO(Comment comment){
+        return CommentResponse.builder()
+                .id(comment.getId())
+                .commentFriendResponse(convertToCommentFriendResponseDTO(comment.getMember()))
+                .content(comment.getContent())
+                .createdAt(comment.getCreateAt())
+                .build();
+    }
+}
+
diff --git a/src/main/java/com/potatocake/everymoment/service/DiaryService.java b/src/main/java/com/potatocake/everymoment/service/DiaryService.java
index e8bf635..8debdc8 100644
--- a/src/main/java/com/potatocake/everymoment/service/DiaryService.java
+++ b/src/main/java/com/potatocake/everymoment/service/DiaryService.java
@@ -18,6 +18,7 @@
 import com.potatocake.everymoment.exception.GlobalException;
 import com.potatocake.everymoment.repository.DiaryCategoryRepository;
 import com.potatocake.everymoment.repository.DiaryRepository;
+import com.potatocake.everymoment.repository.MemberRepository;
 import com.potatocake.everymoment.repository.NotificationRepository;
 import com.potatocake.everymoment.security.MemberDetails;
 import java.util.ArrayList;
@@ -29,6 +30,7 @@
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.jpa.domain.Specification;
 import org.springframework.security.core.Authentication;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.security.core.context.SecurityContextHolder;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -41,16 +43,16 @@ public class DiaryService {
     private final DiaryRepository diaryRepository;
     private final DiaryCategoryRepository diaryCategoryRepository;
     private final NotificationRepository notificationRepository;
+    private final MemberRepository memberRepository;
 
     // 자동 일기 저장 (LocationPoint, Name, Adress 만 저장)
-    public NotificationResponse createDiaryAuto(DiaryAutoCreateRequest diaryAutoCreateRequest) {
+    public NotificationResponse createDiaryAuto(Long memberId, DiaryAutoCreateRequest diaryAutoCreateRequest) {
         // member 가져옴
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         Diary diary = Diary.builder()
-                .memberId(currentMember)
+                .member(currentMember)
                 .locationPoint(diaryAutoCreateRequest.getLocationPoint().toString())
                 .locationName(diaryAutoCreateRequest.getLocationName())
                 .address(diaryAutoCreateRequest.getAddress())
@@ -62,7 +64,7 @@ public NotificationResponse createDiaryAuto(DiaryAutoCreateRequest diaryAutoCrea
         String content = "현재 " + savedDiary.getLocationName() + "에 머무르고 있어요! 지금 기분은 어떠신가요?";
 
         Notification notification = Notification.builder()
-                .memberId(currentMember)
+                .member(currentMember)
                 .content(content)
                 .type("MOOD_CHECK")
                 .targetId(savedDiary.getId())
@@ -83,14 +85,13 @@ public NotificationResponse createDiaryAuto(DiaryAutoCreateRequest diaryAutoCrea
     }
 
     // 수동 일기 작성
-    public void createDiaryManual(DiaryManualCreateRequest diaryManualCreateRequest) {
+    public void createDiaryManual(Long memberId, DiaryManualCreateRequest diaryManualCreateRequest) {
         // member Id
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         Diary diary = Diary.builder()
-                .memberId(currentMember)
+                .member(currentMember)
                 .content(diaryManualCreateRequest.getContent())
                 .locationPoint(diaryManualCreateRequest.getLocationPoint().toString())
                 .locationName(diaryManualCreateRequest.getLocationName())
@@ -109,11 +110,10 @@ public void createDiaryManual(DiaryManualCreateRequest diaryManualCreateRequest)
 
     // 내 일기 전체 조회 (타임라인)
     @Transactional(readOnly = true)
-    public MyDiariesResponse getMyDiaries(DiaryFilterRequest diaryFilterRequest) {
+    public MyDiariesResponse getMyDiaries(Long memberId, DiaryFilterRequest diaryFilterRequest) {
         //member 가져옴
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         Page<Diary> diaryPage;
 
@@ -133,7 +133,7 @@ public MyDiariesResponse getMyDiaries(DiaryFilterRequest diaryFilterRequest) {
 
             // Diary 중에 memberId같은 것 가져옴
             List<Long> DiaryIdList = diaryCategoryList.stream()
-                    .filter(diaryCategory -> diaryCategory.getDiary().getMemberId()
+                    .filter(diaryCategory -> diaryCategory.getDiary().getMember()
                             .equals(currentMember)) // memberId가 일치하는 경우 필터링
                     .map(diaryCategory -> diaryCategory.getDiary().getId())
                     .collect(Collectors.toList());
@@ -158,14 +158,14 @@ public MyDiariesResponse getMyDiaries(DiaryFilterRequest diaryFilterRequest) {
 
     // 내 일기 상세 조회
     @Transactional(readOnly = true)
-    public MyDiaryResponse getMyDiary(Long id) {
-        Diary diary = getExistDiary(id);
+    public MyDiaryResponse getMyDiary(Long memberId, Long diaryId) {
+        Diary diary = getExistDiary(memberId, diaryId);
         return convertToMyDiaryResponseDto(diary);
     }
 
     // 내 일기 수정
-    public void updateDiary(Long id, DiaryManualCreateRequest diaryManualCreateRequest) {
-        Diary existingDiary = getExistDiary(id);
+    public void updateDiary(Long memberId, Long diaryId, DiaryManualCreateRequest diaryManualCreateRequest) {
+        Diary existingDiary = getExistDiary(memberId, diaryId);
 
         //카테고리 업데이트
         //파일 업데이트
@@ -182,33 +182,32 @@ public void updateDiary(Long id, DiaryManualCreateRequest diaryManualCreateReque
     }
 
     // 내 일기 삭제
-    public void deleteDiary(Long id) {
-        Diary existingDiary = getExistDiary(id);
+    public void deleteDiary(Long memberId, Long diaryId) {
+        Diary existingDiary = getExistDiary(memberId, diaryId);
         diaryRepository.delete(existingDiary);
     }
 
     // 내 일기 북마크 설정
-    public void toggleBookmark(Long id) {
-        Diary existingDiary = getExistDiary(id);
+    public void toggleBookmark(Long memberId, Long diaryId) {
+        Diary existingDiary = getExistDiary(memberId, diaryId);
         existingDiary.toggleBookmark();
     }
 
     // 내 일기 공개 설정
-    public void togglePrivacy(Long id) {
-        Diary existingDiary = getExistDiary(id);
+    public void togglePrivacy(Long memberId, Long diaryId) {
+        Diary existingDiary = getExistDiary(memberId, diaryId);
         existingDiary.togglePublic();
     }
 
     // 로그인한 유저의 일기가 맞는지 확인 후 일기 반환
-    private Diary getExistDiary(Long diaryId) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+    private Diary getExistDiary(Long memberId, Long diaryId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         Diary diary = diaryRepository.findById(diaryId)
                 .orElseThrow(() -> new GlobalException(ErrorCode.DIARY_NOT_FOUND));
 
-        if (!Objects.equals(currentMember.getId(), diary.getMemberId().getId())) {
+        if (!Objects.equals(currentMember.getId(), diary.getMember().getId())) {
             throw new GlobalException(ErrorCode.DIARY_NOT_FOUND);
         }
 
diff --git a/src/main/java/com/potatocake/everymoment/service/FriendDiaryService.java b/src/main/java/com/potatocake/everymoment/service/FriendDiaryService.java
index d6d4ee1..7a8fa74 100644
--- a/src/main/java/com/potatocake/everymoment/service/FriendDiaryService.java
+++ b/src/main/java/com/potatocake/everymoment/service/FriendDiaryService.java
@@ -15,6 +15,7 @@
 import com.potatocake.everymoment.repository.DiaryCategoryRepository;
 import com.potatocake.everymoment.repository.DiaryRepository;
 import com.potatocake.everymoment.repository.FriendRepository;
+import com.potatocake.everymoment.repository.MemberRepository;
 import com.potatocake.everymoment.security.MemberDetails;
 import java.util.ArrayList;
 import java.util.List;
@@ -35,12 +36,12 @@ public class FriendDiaryService {
     private final DiaryRepository diaryRepository;
     private final DiaryCategoryRepository diaryCategoryRepository;
     private final FriendRepository friendRepository;
+    private final MemberRepository memberRepository;
 
     //친구 일기 조회
-    public FriendDiariesResponse getFriendDiaries(DiaryFilterRequest diaryFilterRequest) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+    public FriendDiariesResponse getFriendDiaries(Long memberId, DiaryFilterRequest diaryFilterRequest) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         List<Member> friends = friendRepository.findAllFriendIdsByMemberId(currentMember);
         List<Long> friendIdList = friends.stream()
@@ -63,7 +64,7 @@ public FriendDiariesResponse getFriendDiaries(DiaryFilterRequest diaryFilterRequ
 
             // Diary중에 memberId같은 것 가져옴
             List<Long> filteredDiaryIds = diaryCategories.stream()
-                    .filter(diaryCategory -> friendIdList.contains(diaryCategory.getDiary().getMemberId())) // memberIds 목록에서 필터링
+                    .filter(diaryCategory -> friendIdList.contains(diaryCategory.getDiary().getMember())) // memberIds 목록에서 필터링
                     .map(diaryCategory -> diaryCategory.getDiary().getId())
                     .collect(Collectors.toList());
 
@@ -87,21 +88,20 @@ public FriendDiariesResponse getFriendDiaries(DiaryFilterRequest diaryFilterRequ
     }
 
     // 친구 다이어리 하나 조회
-    public FriendDiaryResponse getFriendDiary(Long id) {
-        Diary diary = diaryRepository.findById(id)
+    public FriendDiaryResponse getFriendDiary(Long memberId, Long diaryId) {
+        Diary diary = diaryRepository.findById(diaryId)
                 .orElseThrow(() -> new IllegalArgumentException("Diary not found"));
 
         //글쓴사람이 친구인지 확인
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         List<Member> friends = friendRepository.findAllFriendIdsByMemberId(currentMember);
         List<Long> friendIdList = friends.stream()
                 .map(Member::getId)
                 .collect(Collectors.toList());
 
-        if(!friendIdList.contains(diary.getMemberId())){
+        if(!friendIdList.contains(diary.getMember())){
             throw new GlobalException(ErrorCode.FRIEND_NOT_FOUND);
         }
         //카테고리 찾음
diff --git a/src/main/java/com/potatocake/everymoment/service/FriendService.java b/src/main/java/com/potatocake/everymoment/service/FriendService.java
index ba78771..f6b5b88 100644
--- a/src/main/java/com/potatocake/everymoment/service/FriendService.java
+++ b/src/main/java/com/potatocake/everymoment/service/FriendService.java
@@ -38,22 +38,20 @@ public class FriendService {
 
     //특정 친구 일기 조회
     @Transactional(readOnly = true)
-    public OneFriendDiariesResponse OneFriendDiariesResponse(Long id, LocalDate date, int key, int size) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+    public OneFriendDiariesResponse OneFriendDiariesResponse(Long memberid, Long friendId, LocalDate date, int key, int size) {
+        Member currentMember = memberRepository.findById(memberid)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         //친구인지 확인
-        Member friend = memberRepository.findById(id)
+        Member friend = memberRepository.findById(friendId)
                 .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
         friendRepository.findByMemberIdAndFriendId(currentMember, friend)
                 .orElseThrow(() -> new GlobalException(ErrorCode.FRIEND_NOT_FOUND));
 
         Pageable pageable = PageRequest.of(key, size);
 
-        Page<Diary> diaries = diaryRepository.findAll(
-                DiarySpecification.filterDiaries(null, null, date, null, null, null)
-                        .and((root, query, builder) -> builder.equal(root.get("memberId").get("id"), id)), pageable);
+        Page<Diary> diaries = diaryRepository.findAll(DiarySpecification.filterDiaries(null, null, date, null, null, null)
+                .and((root, query, builder) -> builder.equal(root.get("memberId").get("id"), friendId)), pageable);
 
         List<FriendDiarySimpleResponse> diaryList = diaries.getContent().stream()
                 .map(this::convertToFriendDiariesResponseDTO)
@@ -69,10 +67,10 @@ public OneFriendDiariesResponse OneFriendDiariesResponse(Long id, LocalDate date
 
     //내 친구 목록 조회
     @Transactional(readOnly = true)
-    public FriendListResponse getFriendList(String nickname, int key, int size) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
+    public FriendListResponse getFriendList(Long memberIdFromController, String nickname, int key, int size) {
+        Member currentMember = memberRepository.findById(memberIdFromController)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+  
         Long memberId = currentMember.getId();
 
         Pageable pageable = PageRequest.of(key, size);
@@ -95,12 +93,10 @@ public FriendListResponse getFriendList(String nickname, int key, int size) {
     }
 
     // 친구 삭제
-    public void deleteFriend(Long id) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
-
-        Member friendMember = memberRepository.findById(id)
+    public void deleteFriend(Long memberId, Long firendId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+        Member friendMember = memberRepository.findById(firendId)
                 .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
 
         Friend friendMine = friendRepository.findByMemberIdAndFriendId(currentMember, friendMember)
@@ -113,13 +109,12 @@ public void deleteFriend(Long id) {
     }
 
     // 친한 친구 설정(토글)
-    public void toggleCloseFriend(Long id) {
-        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        MemberDetails memberDetails = (MemberDetails) authentication.getPrincipal();
-        Member currentMember = memberDetails.getMember();
-
-        Member friendMember = memberRepository.findById(id)
+    public void toggleCloseFriend(Long memberId, Long friendId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+        Member friendMember = memberRepository.findById(friendId)
                 .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+
         Friend friend = friendRepository.findByMemberIdAndFriendId(currentMember, friendMember)
                 .orElseThrow(() -> new GlobalException(ErrorCode.FRIEND_NOT_FOUND));
 
diff --git a/src/main/java/com/potatocake/everymoment/service/NotificationService.java b/src/main/java/com/potatocake/everymoment/service/NotificationService.java
new file mode 100644
index 0000000..e199a24
--- /dev/null
+++ b/src/main/java/com/potatocake/everymoment/service/NotificationService.java
@@ -0,0 +1,61 @@
+package com.potatocake.everymoment.service;
+
+import com.potatocake.everymoment.dto.response.NotificationListResponse;
+import com.potatocake.everymoment.entity.Member;
+import com.potatocake.everymoment.entity.Notification;
+import com.potatocake.everymoment.exception.ErrorCode;
+import com.potatocake.everymoment.exception.GlobalException;
+import com.potatocake.everymoment.repository.MemberRepository;
+import com.potatocake.everymoment.repository.NotificationRepository;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@RequiredArgsConstructor
+@Transactional
+@Service
+public class NotificationService {
+
+    private final NotificationRepository notificationRepository;
+    private final MemberRepository memberRepository;
+
+    public List<NotificationListResponse> getNotifications(Long memberId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+
+        List<Notification> notifications = notificationRepository.findAllByMemberId(currentMember.getId());
+
+        return notifications.stream()
+                .map(this::convertToNotificationResponseDTO)
+                .collect(Collectors.toList());
+    }
+
+    public void updateNotification(Long memberId, Long notificationId) {
+        Member currentMember = memberRepository.findById(memberId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.MEMBER_NOT_FOUND));
+
+        Notification notification = notificationRepository.findById(notificationId)
+                .orElseThrow(() -> new GlobalException(ErrorCode.NOTIFICATION_NOT_FOUND));
+
+        if(!Objects.equals(currentMember.getId(), notification.getMember().getId())){
+            throw new GlobalException(ErrorCode.NOTIFICATION_NOT_FOUND);
+        }
+
+        notification.updateIsRead();
+    }
+
+    // 알림 DTO 변환
+    private NotificationListResponse convertToNotificationResponseDTO(Notification notification){
+        return NotificationListResponse.builder()
+                .id(notification.getId())
+                .content(notification.getContent())
+                .isRead(notification.isRead())
+                .type(notification.getType())
+                .targetId(notification.getTargetId())
+                .createdAt(notification.getCreateAt())
+                .build();
+    }
+}