diff --git a/src/mocks/services/taskServiceHandler.ts b/src/mocks/services/taskServiceHandler.ts
index 112b828e..95546a63 100644
--- a/src/mocks/services/taskServiceHandler.ts
+++ b/src/mocks/services/taskServiceHandler.ts
@@ -1,5 +1,5 @@
 import { http, HttpResponse } from 'msw';
-import { STATUS_DUMMY, TASK_DUMMY } from '@mocks/mockData';
+import { STATUS_DUMMY, TASK_DUMMY, TASK_USER_DUMMY } from '@mocks/mockData';
 import { getStatusHash, getTaskHash } from '@mocks/mockHash';
 import type { TaskForm, TaskOrderForm } from '@/types/TaskType';
 
@@ -28,17 +28,19 @@ const taskServiceHandler = [
   // 일정 생성 API
   http.post(`${BASE_URL}/project/:projectId/task`, async ({ request, params }) => {
     const accessToken = request.headers.get('Authorization');
-    const formData = (await request.json()) as TaskForm;
+    const { assignees, ...restFormData } = (await request.json()) as TaskForm;
     const { projectId } = params;
 
     if (!accessToken) return new HttpResponse(null, { status: 401 });
 
     const statusList = STATUS_DUMMY.filter((status) => status.projectId === Number(projectId));
-    if (!statusList.find((status) => status.statusId === Number(formData.statusId))) {
+    if (!statusList.find((status) => status.statusId === Number(restFormData.statusId))) {
       return new HttpResponse(null, { status: 400 });
     }
 
-    TASK_DUMMY.push({ ...formData, statusId: +formData.statusId, taskId: TASK_DUMMY.length + 1, files: [] });
+    const taskId = TASK_DUMMY.length + 1;
+    assignees.forEach((userId) => TASK_USER_DUMMY.push({ taskId, userId }));
+    TASK_DUMMY.push({ ...restFormData, statusId: +restFormData.statusId, taskId, files: [] });
     return new HttpResponse(null, { status: 201 });
   }),
   // 일정 순서 변경 API