diff --git a/src/components/AudioDetail.vue b/src/components/AudioDetail.vue
index 9c40ac398b..ded5d1784c 100644
--- a/src/components/AudioDetail.vue
+++ b/src/components/AudioDetail.vue
@@ -503,9 +503,16 @@ export default defineComponent({
           audioKey: props.activeAudioKey,
         });
       } catch (e) {
+        let msg: string | undefined;
+        // FIXME: GENERATE_AUDIO_FROM_AUDIO_ITEMのエラーを変えた場合変更する
+        if (e instanceof Error && e.message === "VALID_MOPHING_ERROR") {
+          msg = "モーフィングの設定が無効です。";
+        } else {
+          window.electron.logError(e);
+        }
         $q.dialog({
           title: "再生に失敗しました",
-          message: "エンジンの再起動をお試しください。",
+          message: msg ?? "エンジンの再起動をお試しください。",
           ok: {
             label: "閉じる",
             flat: true,
diff --git a/src/components/AudioInfo.vue b/src/components/AudioInfo.vue
index d1f40c6d3b..56d6d8b5b5 100644
--- a/src/components/AudioInfo.vue
+++ b/src/components/AudioInfo.vue
@@ -392,6 +392,92 @@
         @pan="postPhonemeLengthSlider.qSliderProps.onPan"
       />
     </div>
+    <div
+      v-if="shouldShowMorphing"
+      class="q-px-md"
+      :class="{
+        disabled: uiLocked,
+      }"
+    >
+      <q-separator class="q-mb-md" />
+      <span class="text-body1 q-mb-xs">モーフィング</span>
+      <div class="row no-wrap items-center">
+        <character-button
+          class="q-my-xs"
+          :character-infos="mophingTargetCharacters"
+          :show-engine-info="mophingTargetEngines.length >= 2"
+          :emptiable="true"
+          :ui-locked="uiLocked"
+          v-model:selected-voice="morphingTargetVoice"
+        />
+        <div class="q-pl-xs overflow-hidden">
+          <div class="text-body2 text-no-wrap ellipsis overflow-hidden">
+            {{
+              morphingTargetCharacterInfo
+                ? morphingTargetCharacterInfo.metas.speakerName
+                : "未設定"
+            }}
+          </div>
+          <div
+            v-if="
+              morphingTargetCharacterInfo &&
+              morphingTargetCharacterInfo.metas.styles.length >= 2
+            "
+            class="text-body2 text-no-wrap ellipsis overflow-hidden"
+          >
+            ({{
+              morphingTargetStyleInfo
+                ? morphingTargetStyleInfo.styleName
+                : undefined
+            }})
+          </div>
+        </div>
+      </div>
+      <div
+        v-if="!isSupportedMorphing"
+        class="text-warning"
+        style="font-size: 0.7rem"
+      >
+        非対応エンジンです
+      </div>
+      <div
+        v-else-if="isValidMorphingInfo"
+        class="text-warning"
+        style="font-size: 0.7rem"
+      >
+        無効な設定です
+      </div>
+      <div :class="{ disabled: morphingTargetStyleInfo == undefined }">
+        <span class="text-body1 q-mb-xs"
+          >割合
+          {{
+            morphingRateSlider.state.currentValue.value != undefined
+              ? morphingRateSlider.state.currentValue.value.toFixed(2)
+              : undefined
+          }}</span
+        >
+        <q-slider
+          dense
+          snap
+          color="primary-light"
+          trackSize="2px"
+          :min="morphingRateSlider.qSliderProps.min.value"
+          :max="morphingRateSlider.qSliderProps.max.value"
+          :step="morphingRateSlider.qSliderProps.step.value"
+          :disable="
+            morphingRateSlider.qSliderProps.disable.value ||
+            morphingTargetStyleInfo == undefined
+          "
+          :model-value="morphingRateSlider.qSliderProps.modelValue.value"
+          @update:model-value="
+            morphingRateSlider.qSliderProps['onUpdate:modelValue']
+          "
+          @change="morphingRateSlider.qSliderProps.onChange"
+          @wheel="morphingRateSlider.qSliderProps.onWheel"
+          @pan="morphingRateSlider.qSliderProps.onPan"
+        />
+      </div>
+    </div>
   </div>
 </template>
 
@@ -400,8 +486,9 @@ import { computed, defineComponent, ref } from "vue";
 import { QSelectProps } from "quasar";
 import { useStore } from "@/store";
 
-import { Preset } from "@/type/preload";
+import { MorphingInfo, Preset, Voice } from "@/type/preload";
 import { previewSliderHelper } from "@/helpers/previewSliderHelper";
+import CharacterButton from "./CharacterButton.vue";
 import PresetManageDialog from "./PresetManageDialog.vue";
 import { EngineManifest } from "@/openapi";
 
@@ -409,6 +496,7 @@ export default defineComponent({
   name: "AudioInfo",
 
   components: {
+    CharacterButton,
     PresetManageDialog,
   },
 
@@ -485,6 +573,22 @@ export default defineComponent({
       });
     };
 
+    const setMorphingRate = (rate: number) => {
+      const info = audioItem.value.morphingInfo;
+      if (info == undefined) {
+        throw new Error("audioItem.value.morphingInfo == undefined");
+      }
+      store.dispatch("COMMAND_SET_MORPHING_INFO", {
+        audioKey: props.activeAudioKey,
+        morphingInfo: {
+          rate,
+          targetEngineId: info.targetEngineId,
+          targetSpeakerId: info.targetSpeakerId,
+          targetStyleId: info.targetStyleId,
+        },
+      });
+    };
+
     const speedScaleSlider = previewSliderHelper({
       modelValue: () => query.value?.speedScale ?? null,
       disable: () =>
@@ -550,6 +654,89 @@ export default defineComponent({
       scrollMinStep: () => 0.01,
     });
 
+    // モーフィング
+    const shouldShowMorphing = computed(
+      () => store.state.experimentalSetting.enableMorphing
+    );
+
+    const isSupportedMorphing = computed(
+      () => supportedFeatures.value?.synthesisMorphing
+    );
+
+    const isValidMorphingInfo = computed(() => {
+      if (audioItem.value.morphingInfo == undefined) return false;
+      return !store.getters.VALID_MOPHING_INFO(audioItem.value);
+    });
+
+    const mophingTargetEngines = store.getters.MORPHING_SUPPORTED_ENGINES;
+
+    const mophingTargetCharacters = computed(() => {
+      const allCharacters = store.getters.GET_ORDERED_ALL_CHARACTER_INFOS;
+      return allCharacters
+        .map((character) => {
+          const targetStyles = character.metas.styles.filter((style) =>
+            mophingTargetEngines.includes(style.engineId)
+          );
+          character.metas.styles = targetStyles;
+          return character;
+        })
+        .filter((characters) => characters.metas.styles.length >= 1);
+    });
+
+    const morphingTargetVoice = computed({
+      get() {
+        const morphingInfo = audioItem.value.morphingInfo;
+        if (morphingInfo == undefined) return undefined;
+        return {
+          engineId: morphingInfo.targetEngineId,
+          speakerId: morphingInfo.targetSpeakerId,
+          styleId: morphingInfo.targetStyleId,
+        };
+      },
+      set(voice: Voice | undefined) {
+        const morphingInfo =
+          voice != undefined
+            ? {
+                rate: audioItem.value.morphingInfo?.rate ?? 0.5,
+                targetEngineId: voice.engineId,
+                targetSpeakerId: voice.speakerId,
+                targetStyleId: voice.styleId,
+              }
+            : undefined;
+        store.dispatch("COMMAND_SET_MORPHING_INFO", {
+          audioKey: props.activeAudioKey,
+          morphingInfo,
+        });
+      },
+    });
+
+    const morphingTargetCharacterInfo = computed(() =>
+      mophingTargetCharacters.value.find(
+        (character) =>
+          character.metas.speakerUuid === morphingTargetVoice.value?.speakerId
+      )
+    );
+
+    const morphingTargetStyleInfo = computed(() => {
+      const targetVoice = morphingTargetVoice.value;
+      return morphingTargetCharacterInfo.value?.metas.styles.find(
+        (style) =>
+          style.engineId === targetVoice?.engineId &&
+          style.styleId === targetVoice.styleId
+      );
+    });
+
+    const morphingRateSlider = previewSliderHelper({
+      modelValue: () => audioItem.value.morphingInfo?.rate ?? null,
+      disable: () => uiLocked.value,
+      onChange: setMorphingRate,
+      max: () => 1,
+      min: () => 0,
+      step: () => 0.01,
+      scrollStep: () => 0.1,
+      scrollMinStep: () => 0.01,
+    });
+
     // プリセット
     const enablePreset = computed(
       () => store.state.experimentalSetting.enablePreset
@@ -572,13 +759,30 @@ export default defineComponent({
       if (audioPresetKey.value == undefined)
         throw new Error("audioPresetKey is undefined"); // 次のコードが何故かコンパイルエラーになるチェック
       const preset = presetItems.value[audioPresetKey.value];
-      const { name: _, ...presetParts } = preset;
+      const { name: _, morphingInfo, ...presetParts } = preset;
 
       // 入力パラメータと比較
-      const keys = Object.keys(presetParts) as (keyof Omit<Preset, "name">)[];
-      return keys.some(
-        (key) => presetParts[key] !== presetPartsFromParameter.value[key]
-      );
+      const keys = Object.keys(presetParts) as (keyof Omit<
+        Preset,
+        "name" | "morphingInfo"
+      >)[];
+      if (
+        keys.some(
+          (key) => presetParts[key] !== presetPartsFromParameter.value[key]
+        )
+      )
+        return true;
+      const morphingInfoFromParameter =
+        presetPartsFromParameter.value.morphingInfo;
+      if (morphingInfo && morphingInfoFromParameter) {
+        const morphingInfoKeys = Object.keys(
+          morphingInfo
+        ) as (keyof MorphingInfo)[];
+        return morphingInfoKeys.some(
+          (key) => morphingInfo[key] !== morphingInfoFromParameter[key]
+        );
+      }
+      return morphingInfo != morphingInfoFromParameter;
     });
 
     type PresetSelectModelType = {
@@ -737,6 +941,18 @@ export default defineComponent({
         volumeScale: volumeScaleSlider.state.currentValue.value,
         prePhonemeLength: prePhonemeLengthSlider.state.currentValue.value,
         postPhonemeLength: postPhonemeLengthSlider.state.currentValue.value,
+        morphingInfo:
+          morphingTargetStyleInfo.value &&
+          morphingTargetCharacterInfo.value &&
+          morphingRateSlider.state.currentValue.value != undefined // FIXME: ifでチェックしてthrowする
+            ? {
+                rate: morphingRateSlider.state.currentValue.value,
+                targetEngineId: morphingTargetStyleInfo.value.engineId,
+                targetSpeakerId:
+                  morphingTargetCharacterInfo.value.metas.speakerUuid,
+                targetStyleId: morphingTargetStyleInfo.value.styleId,
+              }
+            : undefined,
       };
     });
 
@@ -895,6 +1111,7 @@ export default defineComponent({
       setAudioVolumeScale,
       setAudioPrePhonemeLength,
       setAudioPostPhonemeLength,
+      setMorphingRate,
       applyPreset,
       enablePreset,
       isRegisteredPreset,
@@ -920,6 +1137,15 @@ export default defineComponent({
       volumeScaleSlider,
       prePhonemeLengthSlider,
       postPhonemeLengthSlider,
+      mophingTargetEngines,
+      shouldShowMorphing,
+      isSupportedMorphing,
+      isValidMorphingInfo,
+      mophingTargetCharacters,
+      morphingTargetVoice,
+      morphingTargetCharacterInfo,
+      morphingTargetStyleInfo,
+      morphingRateSlider,
       handleChangeSpeedScaleInput,
       handleChangePitchScaleInput,
       handleChangeIntonationInput,
diff --git a/src/components/CharacterButton.vue b/src/components/CharacterButton.vue
index fffc6f638c..66639a0e1a 100644
--- a/src/components/CharacterButton.vue
+++ b/src/components/CharacterButton.vue
@@ -24,9 +24,9 @@
       transition-show="none"
       transition-hide="none"
     >
-      <q-list>
+      <q-list style="min-width: max-content">
         <q-item
-          v-if="selectedStyleInfo == undefined"
+          v-if="selectedStyleInfo == undefined && !emptiable"
           class="row no-wrap items-center"
         >
           <span class="text-warning vertical-middle"
@@ -123,7 +123,7 @@
                   class="character-menu"
                   v-model="subMenuOpenFlags[characterIndex]"
                 >
-                  <q-list>
+                  <q-list style="min-width: max-content">
                     <q-item
                       v-for="(style, styleIndex) in characterInfo.metas.styles"
                       :key="styleIndex"
@@ -221,6 +221,7 @@ export default defineComponent({
 
     const selectedCharacter = computed(() => {
       const selectedVoice = props.selectedVoice;
+      if (selectedVoice == undefined) return undefined;
       const character = props.characterInfos.find(
         (characterInfo) =>
           characterInfo.metas.speakerUuid === selectedVoice?.speakerId &&
@@ -261,9 +262,10 @@ export default defineComponent({
         (x) => x.speakerUuid === speakerUuid
       )?.defaultStyleId;
 
-      const defaultStyle = characterInfo?.metas.styles.find(
-        (style) => style.styleId === defaultStyleId
-      );
+      const defaultStyle =
+        characterInfo?.metas.styles.find(
+          (style) => style.styleId === defaultStyleId
+        ) ?? characterInfo?.metas.styles[0]; // デフォルトのスタイルIDが見つからない場合stylesの先頭を選択する
 
       if (defaultStyle == undefined)
         throw new Error("defaultStyle == undefined");
diff --git a/src/components/Dialog.ts b/src/components/Dialog.ts
index 9ac6fd05fa..dc82c48bd1 100644
--- a/src/components/Dialog.ts
+++ b/src/components/Dialog.ts
@@ -2,7 +2,7 @@ import { Encoding as EncodingType } from "@/type/preload";
 import {
   AllActions,
   SaveResultObject,
-  WriteErrorTypeForSaveAllResultDialog,
+  ErrorTypeForSaveAllResultDialog,
 } from "@/store/type";
 import SaveAllResultDialog from "@/components/SaveAllResultDialog.vue";
 import { QVueGlobals } from "quasar";
@@ -45,8 +45,12 @@ export async function generateAndSaveOneAudioWithDialog({
       }
       break;
     case "ENGINE_ERROR":
-      msg =
-        "エンジンのエラーによって失敗しました。エンジンの再起動をお試しください。";
+      if (result.errorMessage) {
+        msg = result.errorMessage;
+      } else {
+        msg =
+          "エンジンのエラーによって失敗しました。エンジンの再起動をお試しください。";
+      }
       break;
   }
   quasarDialog({
@@ -82,8 +86,8 @@ export async function generateAndSaveAllAudioWithDialog({
   );
 
   const successArray: Array<string | undefined> = [];
-  const writeErrorArray: Array<WriteErrorTypeForSaveAllResultDialog> = [];
-  const engineErrorArray: Array<string | undefined> = [];
+  const writeErrorArray: Array<ErrorTypeForSaveAllResultDialog> = [];
+  const engineErrorArray: Array<ErrorTypeForSaveAllResultDialog> = [];
 
   if (result) {
     for (const item of result) {
@@ -105,7 +109,7 @@ export async function generateAndSaveAllAudioWithDialog({
           writeErrorArray.push({ path: path, message: msg });
           break;
         case "ENGINE_ERROR":
-          engineErrorArray.push(path);
+          engineErrorArray.push({ path: path, message: msg });
           break;
       }
     }
@@ -154,15 +158,19 @@ export async function generateAndConnectAndSaveAudioWithDialog({
   let msg = "";
   switch (result.result) {
     case "WRITE_ERROR":
-      if (result.errorMessage) {
+      if (result.errorMessage != undefined) {
         msg = result.errorMessage;
       } else {
         msg = "何らかの理由で書き出しに失敗しました。ログを参照してください。";
       }
       break;
     case "ENGINE_ERROR":
-      msg =
-        "エンジンのエラーによって失敗しました。エンジンの再起動をお試しください。";
+      if (result.errorMessage != undefined) {
+        msg = result.errorMessage;
+      } else {
+        msg =
+          "エンジンのエラーによって失敗しました。エンジンの再起動をお試しください。";
+      }
       break;
   }
 
diff --git a/src/components/DictionaryManageDialog.vue b/src/components/DictionaryManageDialog.vue
index 690596e430..b7a42fc76b 100644
--- a/src/components/DictionaryManageDialog.vue
+++ b/src/components/DictionaryManageDialog.vue
@@ -483,12 +483,14 @@ export default defineComponent({
         audioItem,
       });
       if (!blob) {
-        blob = await createUILockAction(
-          store.dispatch("GENERATE_AUDIO_FROM_AUDIO_ITEM", {
-            audioItem,
-          })
-        );
-        if (!blob) {
+        try {
+          blob = await createUILockAction(
+            store.dispatch("GENERATE_AUDIO_FROM_AUDIO_ITEM", {
+              audioItem,
+            })
+          );
+        } catch (e) {
+          window.electron.logError(e);
           nowGenerating.value = false;
           $q.dialog({
             title: "生成に失敗しました",
diff --git a/src/components/HeaderBar.vue b/src/components/HeaderBar.vue
index 60e9800fce..d3880b9400 100644
--- a/src/components/HeaderBar.vue
+++ b/src/components/HeaderBar.vue
@@ -109,10 +109,14 @@ export default defineComponent({
     const playContinuously = async () => {
       try {
         await store.dispatch("PLAY_CONTINUOUSLY_AUDIO");
-      } catch {
+      } catch (e) {
+        let msg: string | undefined;
+        if (e instanceof Error && e.message !== "") {
+          msg = e.message;
+        }
         $q.dialog({
           title: "再生に失敗しました",
-          message: "エンジンの再起動をお試しください。",
+          message: msg ?? "エンジンの再起動をお試しください。",
           ok: {
             label: "閉じる",
             flat: true,
diff --git a/src/components/SaveAllResultDialog.vue b/src/components/SaveAllResultDialog.vue
index c76b6036cf..66ae8f8c66 100644
--- a/src/components/SaveAllResultDialog.vue
+++ b/src/components/SaveAllResultDialog.vue
@@ -1,94 +1,107 @@
-<template>
-  <q-dialog persistent ref="dialogRef">
-    <!-- 仮デザイン -->
-    <q-layout container class="q-dialog-plugin bg-background">
-      <q-header>
-        <q-toolbar>
-          <q-toolbar-title class="text-display"
-            >音声書き出し結果</q-toolbar-title
-          >
-        </q-toolbar>
-        <q-space />
-      </q-header>
-      <q-page-container>
-        <q-page>
-          <q-list separator v-if="writeErrorArray.length > 0">
-            <div class="error">失敗（書き込みエラー）:</div>
-            <q-item v-for="(value, index) in writeErrorArray" :key="index">
-              <q-item-section>
-                <q-item-label>{{ value.path }}</q-item-label>
-                <q-item-label>詳細：{{ value.message }}</q-item-label>
-              </q-item-section>
-            </q-item>
-          </q-list>
-          <q-list separator v-if="engineErrorArray.length > 0">
-            <div class="error">失敗（エンジンエラー）:</div>
-            <q-item v-for="(value, index) in engineErrorArray" :key="index">
-              <q-item-section>
-                <q-item-label>{{ value }}</q-item-label>
-              </q-item-section>
-            </q-item>
-          </q-list>
-          <q-list separator v-if="successArray.length > 0">
-            <div class="success">成功:</div>
-            <q-item v-for="(value, index) in successArray" :key="index">
-              <q-item-section>
-                <q-item-label>{{ value }}</q-item-label>
-              </q-item-section>
-            </q-item>
-          </q-list>
-        </q-page>
-      </q-page-container>
-      <q-footer>
-        <q-toolbar>
-          <q-space />
-          <q-btn flat dense align="right" @click="close" label="閉じる" />
-        </q-toolbar>
-      </q-footer>
-    </q-layout>
-  </q-dialog>
-</template>
-
-<script lang="ts">
-import { defineComponent } from "vue";
-import { useDialogPluginComponent } from "quasar";
-
-export default defineComponent({
-  name: "SaveAllResultDialog",
-  props: {
-    successArray: Array,
-    writeErrorArray: Array,
-    engineErrorArray: Array,
-  },
-  emits: {
-    ...useDialogPluginComponent.emits,
-  },
-  setup() {
-    const { dialogRef, onDialogOK } = useDialogPluginComponent();
-    const close = () => onDialogOK();
-    return {
-      dialogRef,
-      close,
-    };
-  },
-});
-</script>
-
-<style scoped lang="scss">
-@use '@/styles/colors' as colors;
-
-.q-page-container {
-  margin-top: 1em;
-}
-
-.q-item {
-  border-bottom: solid 0.1rem colors.$primary;
-}
-
-.success {
-  color: green;
-}
-.error {
-  color: red;
-}
-</style>
+<template>
+  <q-dialog persistent ref="dialogRef">
+    <!-- 仮デザイン -->
+    <q-layout container class="q-dialog-plugin bg-background">
+      <q-header>
+        <q-toolbar>
+          <q-toolbar-title class="text-display"
+            >音声書き出し結果</q-toolbar-title
+          >
+        </q-toolbar>
+        <q-space />
+      </q-header>
+      <q-page-container>
+        <q-page>
+          <q-list separator v-if="writeErrorArray.length > 0">
+            <div class="error">失敗（書き込みエラー）:</div>
+            <q-item v-for="(value, index) in writeErrorArray" :key="index">
+              <q-item-section>
+                <q-item-label>{{ value.path }}</q-item-label>
+                <q-item-label>詳細：{{ value.message }}</q-item-label>
+              </q-item-section>
+            </q-item>
+          </q-list>
+          <q-list separator v-if="engineErrorArray.length > 0">
+            <div class="error">失敗（エンジンエラー）:</div>
+            <q-item v-for="(value, index) in engineErrorArray" :key="index">
+              <q-item-section>
+                <q-item-label>{{ value.path }}</q-item-label>
+                <q-item-label v-if="value.message"
+                  >詳細：{{ value.message }}</q-item-label
+                >
+              </q-item-section>
+            </q-item>
+          </q-list>
+          <q-list separator v-if="successArray.length > 0">
+            <div class="success">成功:</div>
+            <q-item v-for="(value, index) in successArray" :key="index">
+              <q-item-section>
+                <q-item-label>{{ value }}</q-item-label>
+              </q-item-section>
+            </q-item>
+          </q-list>
+        </q-page>
+      </q-page-container>
+      <q-footer>
+        <q-toolbar>
+          <q-space />
+          <q-btn flat dense align="right" @click="close" label="閉じる" />
+        </q-toolbar>
+      </q-footer>
+    </q-layout>
+  </q-dialog>
+</template>
+
+<script lang="ts">
+import { ErrorTypeForSaveAllResultDialog } from "@/store/type";
+import { useDialogPluginComponent } from "quasar";
+import { defineComponent, PropType } from "vue";
+
+export default defineComponent({
+  name: "SaveAllResultDialog",
+  props: {
+    successArray: {
+      type: Array as PropType<string | undefined[]>,
+      required: true,
+    },
+    writeErrorArray: {
+      type: Array as PropType<ErrorTypeForSaveAllResultDialog[]>,
+      required: true,
+    },
+    engineErrorArray: {
+      type: Array as PropType<ErrorTypeForSaveAllResultDialog[]>,
+      required: true,
+    },
+  },
+  emits: {
+    ...useDialogPluginComponent.emits,
+  },
+  setup() {
+    const { dialogRef, onDialogOK } = useDialogPluginComponent();
+    const close = () => onDialogOK();
+    return {
+      dialogRef,
+      close,
+    };
+  },
+});
+</script>
+
+<style scoped lang="scss">
+@use '@/styles/colors' as colors;
+
+.q-page-container {
+  margin-top: 1em;
+}
+
+.q-item {
+  border-bottom: solid 0.1rem colors.$primary;
+}
+
+.success {
+  color: green;
+}
+.error {
+  color: red;
+}
+</style>
diff --git a/src/components/SettingDialog.vue b/src/components/SettingDialog.vue
index bf1ce2afda..2a15acbef9 100644
--- a/src/components/SettingDialog.vue
+++ b/src/components/SettingDialog.vue
@@ -623,6 +623,30 @@
                 >
                 </q-toggle>
               </q-card-actions>
+              <q-card-actions class="q-px-md q-py-none bg-surface">
+                <div>モーフィング機能</div>
+                <div>
+                  <q-icon name="help_outline" size="sm" class="help-hover-icon">
+                    <q-tooltip
+                      :delay="500"
+                      anchor="center left"
+                      self="center right"
+                      transition-show="jump-left"
+                      transition-hide="jump-right"
+                    >
+                      2人の話者でモーフィングした音声を合成する
+                    </q-tooltip>
+                  </q-icon>
+                </div>
+                <q-space />
+                <q-toggle
+                  :model-value="experimentalSetting.enableMorphing"
+                  @update:model-value="
+                    changeExperimentalSetting('enableMorphing', $event)
+                  "
+                >
+                </q-toggle>
+              </q-card-actions>
             </q-card>
             <q-card flat class="setting-card">
               <q-card-actions>
diff --git a/src/helpers/previewSliderHelper.ts b/src/helpers/previewSliderHelper.ts
index 17f96b072c..5e5ecdf119 100644
--- a/src/helpers/previewSliderHelper.ts
+++ b/src/helpers/previewSliderHelper.ts
@@ -25,6 +25,7 @@ export type PreviewSliderHelper = {
     max: Ref<number>;
     step: Ref<number>;
     disable: Ref<boolean>;
+    modelValue: Ref<number | null>;
     "onUpdate:modelValue": (value: number) => void;
     onChange: (value: number) => void;
     onWheel: (event: Events["onWheel"]) => void;
diff --git a/src/store/audio.ts b/src/store/audio.ts
index efdbb4fc44..7c1259f447 100644
--- a/src/store/audio.ts
+++ b/src/store/audio.ts
@@ -18,6 +18,7 @@ import {
   DefaultStyleId,
   Encoding as EncodingType,
   MoraDataType,
+  MorphingInfo,
   StyleInfo,
   WriteFileErrorResult,
 } from "@/type/preload";
@@ -51,6 +52,7 @@ async function generateUniqueIdAndQuery(
       audioQuery,
       audioItem.engineId,
       audioItem.styleId,
+      audioItem.morphingInfo,
       state.experimentalSetting.enableInterrogativeUpspeak, // このフラグが違うと、同じAudioQueryで違う音声が生成されるので追加
     ])
   );
@@ -478,6 +480,7 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
         audioItem.query.outputSamplingRate =
           baseAudioItem.query.outputSamplingRate;
         audioItem.query.outputStereo = baseAudioItem.query.outputStereo;
+        audioItem.morphingInfo = baseAudioItem.morphingInfo;
       }
       return audioItem;
     },
@@ -672,6 +675,41 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
     },
   },
 
+  SET_MORPHING_INFO: {
+    mutation(
+      state,
+      {
+        audioKey,
+        morphingInfo,
+      }: { audioKey: string; morphingInfo: MorphingInfo | undefined }
+    ) {
+      const item = state.audioItems[audioKey];
+      item.morphingInfo = morphingInfo;
+    },
+  },
+
+  MORPHING_SUPPORTED_ENGINES: {
+    getter: (state) =>
+      state.engineIds.filter(
+        (engineId) =>
+          state.engineManifests[engineId].supportedFeatures?.synthesisMorphing
+      ),
+  },
+
+  VALID_MOPHING_INFO: {
+    getter: (_, getters) => (audioItem: AudioItem) => {
+      if (
+        audioItem.morphingInfo == undefined ||
+        audioItem.engineId == undefined
+      )
+        return false;
+      return (
+        getters.MORPHING_SUPPORTED_ENGINES.includes(audioItem.engineId) &&
+        audioItem.engineId === audioItem.morphingInfo.targetEngineId
+      );
+    },
+  },
+
   SET_AUDIO_QUERY: {
     mutation(
       state,
@@ -864,7 +902,7 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
       if (presetItem == undefined) return;
 
       // Filter name property from presetItem in order to extract audioInfos.
-      const { name: _, ...presetAudioInfos } = presetItem;
+      const { name: _, morphingInfo, ...presetAudioInfos } = presetItem;
 
       // Type Assertion
       const audioInfos: Omit<
@@ -873,6 +911,8 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
       > = presetAudioInfos;
 
       audioItem.query = { ...audioItem.query, ...audioInfos };
+
+      audioItem.morphingInfo = morphingInfo;
     },
   },
 
@@ -1037,42 +1077,57 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
 
   GENERATE_AUDIO_FROM_AUDIO_ITEM: {
     action: createUILockAction(
-      async ({ dispatch, state }, { audioItem }: { audioItem: AudioItem }) => {
+      async (
+        { dispatch, getters, state },
+        { audioItem }: { audioItem: AudioItem }
+      ) => {
         const engineId = audioItem.engineId;
         if (engineId === undefined)
-          throw new Error(`engineId is not defined for audioItem`);
+          throw new Error("engineId is not defined for audioItem");
 
         const [id, audioQuery] = await generateUniqueIdAndQuery(
           state,
           audioItem
         );
+        if (audioQuery == undefined)
+          throw new Error("audioQuery is not defined for audioItem");
+
         const speaker = audioItem.styleId;
-        if (audioQuery == undefined || speaker == undefined) {
-          return null;
-        }
+        if (speaker == undefined)
+          throw new Error("speaker is not defined for audioItem");
+
+        const engineAudioQuery = convertAudioQueryFromEditorToEngine(
+          audioQuery,
+          state.engineManifests[engineId].defaultSamplingRate
+        );
 
         return dispatch("INSTANTIATE_ENGINE_CONNECTOR", {
           engineId,
-        })
-          .then((instance) =>
-            instance.invoke("synthesisSynthesisPost")({
-              audioQuery: convertAudioQueryFromEditorToEngine(
-                audioQuery,
-                state.engineManifests[engineId].defaultSamplingRate
-              ),
+        }).then(async (instance) => {
+          let blob: Blob;
+          // FIXME: モーフィングが設定で無効化されていてもモーフィングが行われるので気づけるUIを作成する
+          if (audioItem.morphingInfo != undefined) {
+            if (!getters.VALID_MOPHING_INFO(audioItem))
+              throw new Error("VALID_MOPHING_ERROR"); //FIXME: エラーを変更した場合ハンドリング部分も修正する
+            blob = await instance.invoke(
+              "synthesisMorphingSynthesisMorphingPost"
+            )({
+              audioQuery: engineAudioQuery,
+              baseSpeaker: speaker,
+              targetSpeaker: audioItem.morphingInfo.targetStyleId,
+              morphRate: audioItem.morphingInfo.rate,
+            });
+          } else {
+            blob = await instance.invoke("synthesisSynthesisPost")({
+              audioQuery: engineAudioQuery,
               speaker,
               enableInterrogativeUpspeak:
                 state.experimentalSetting.enableInterrogativeUpspeak,
-            })
-          )
-          .then(async (blob) => {
-            audioBlobCache[id] = blob;
-            return blob;
-          })
-          .catch((e) => {
-            window.electron.logError(e);
-            return null;
-          });
+            });
+          }
+          audioBlobCache[id] = blob;
+          return blob;
+        });
       }
     ),
   },
@@ -1147,9 +1202,21 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
 
         let blob = await dispatch("GET_AUDIO_CACHE", { audioKey });
         if (!blob) {
-          blob = await dispatch("GENERATE_AUDIO", { audioKey });
-          if (!blob) {
-            return { result: "ENGINE_ERROR", path: filePath };
+          try {
+            blob = await dispatch("GENERATE_AUDIO", { audioKey });
+          } catch (e) {
+            let errorMessage = undefined;
+            // FIXME: GENERATE_AUDIO_FROM_AUDIO_ITEMのエラーを変えた場合変更する
+            if (e instanceof Error && e.message === "VALID_MOPHING_ERROR") {
+              errorMessage = "モーフィングの設定が無効です。";
+            } else {
+              window.electron.logError(e);
+            }
+            return {
+              result: "ENGINE_ERROR",
+              path: filePath,
+              errorMessage,
+            };
           }
         }
 
@@ -1344,11 +1411,24 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
         for (const audioKey of state.audioKeys) {
           let blob = await dispatch("GET_AUDIO_CACHE", { audioKey });
           if (!blob) {
-            blob = await dispatch("GENERATE_AUDIO", { audioKey });
-            callback?.(++finishedCount, totalCount);
-          }
-          if (blob === null) {
-            return { result: "ENGINE_ERROR", path: filePath };
+            try {
+              blob = await dispatch("GENERATE_AUDIO", { audioKey });
+            } catch (e) {
+              let errorMessage = undefined;
+              // FIXME: GENERATE_AUDIO_FROM_AUDIO_ITEMのエラーを変えた場合変更する
+              if (e instanceof Error && e.message === "VALID_MOPHING_ERROR") {
+                errorMessage = "モーフィングの設定が無効です。";
+              } else {
+                window.electron.logError(e);
+              }
+              return {
+                result: "ENGINE_ERROR",
+                path: filePath,
+                errorMessage,
+              };
+            } finally {
+              callback?.(++finishedCount, totalCount);
+            }
           }
           const encodedBlob = await base64Encoder(blob);
           if (encodedBlob === undefined) {
@@ -1550,16 +1630,16 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
             audioKey,
             nowGenerating: true,
           });
-          blob = await withProgress(
-            dispatch("GENERATE_AUDIO", { audioKey }),
-            dispatch
-          );
-          commit("SET_AUDIO_NOW_GENERATING", {
-            audioKey,
-            nowGenerating: false,
-          });
-          if (!blob) {
-            throw new Error();
+          try {
+            blob = await withProgress(
+              dispatch("GENERATE_AUDIO", { audioKey }),
+              dispatch
+            );
+          } finally {
+            commit("SET_AUDIO_NOW_GENERATING", {
+              audioKey,
+              nowGenerating: false,
+            });
           }
         }
 
@@ -2504,6 +2584,27 @@ export const audioCommandStore = transformCommandStore(
       },
     },
 
+    COMMAND_SET_MORPHING_INFO: {
+      mutation(
+        draft,
+        payload: {
+          audioKey: string;
+          morphingInfo: MorphingInfo | undefined;
+        }
+      ) {
+        audioStore.mutations.SET_MORPHING_INFO(draft, payload);
+      },
+      action(
+        { commit },
+        payload: {
+          audioKey: string;
+          morphingInfo: MorphingInfo | undefined;
+        }
+      ) {
+        commit("COMMAND_SET_MORPHING_INFO", payload);
+      },
+    },
+
     COMMAND_SET_AUDIO_PRESET: {
       mutation(
         draft,
diff --git a/src/store/project.ts b/src/store/project.ts
index f11bdfbc2d..bb7830da3a 100755
--- a/src/store/project.ts
+++ b/src/store/project.ts
@@ -419,6 +419,15 @@ const audioQuerySchema = {
   },
 } as const;
 
+const morphingInfoSchema = {
+  properties: {
+    rate: { type: "float32" },
+    targetEngineId: { type: "string" },
+    targetSpeakerId: { type: "string" },
+    targetStyleId: { type: "int32" },
+  },
+} as const;
+
 const audioItemSchema = {
   properties: {
     text: { type: "string" },
@@ -428,6 +437,7 @@ const audioItemSchema = {
     styleId: { type: "int32" },
     query: audioQuerySchema,
     presetKey: { type: "string" },
+    morphingInfo: morphingInfoSchema,
   },
 } as const;
 
diff --git a/src/store/setting.ts b/src/store/setting.ts
index 9f72af920d..50c0c115fd 100644
--- a/src/store/setting.ts
+++ b/src/store/setting.ts
@@ -44,6 +44,7 @@ export const settingStoreState: SettingStoreState = {
   experimentalSetting: {
     enablePreset: false,
     enableInterrogativeUpspeak: false,
+    enableMorphing: false,
   },
   splitTextWhenPaste: "PERIOD_AND_NEW_LINE",
   splitterPosition: {
diff --git a/src/store/type.ts b/src/store/type.ts
index 0707b666f4..698700fec3 100644
--- a/src/store/type.ts
+++ b/src/store/type.ts
@@ -29,6 +29,7 @@ import {
   ToolbarSetting,
   UpdateInfo,
   Preset,
+  MorphingInfo,
   ActivePointScrollMode,
   EngineInfo,
   SplitTextWhenPasteType,
@@ -54,6 +55,7 @@ export type AudioItem = {
   styleId?: number;
   query?: EditorAudioQuery;
   presetKey?: string;
+  morphingInfo?: MorphingInfo;
 };
 
 export type AudioState = {
@@ -78,7 +80,7 @@ export type SaveResultObject = {
   path: string | undefined;
   errorMessage?: string;
 };
-export type WriteErrorTypeForSaveAllResultDialog = {
+export type ErrorTypeForSaveAllResultDialog = {
   path: string;
   message: string;
 };
@@ -265,6 +267,21 @@ export type AudioStoreTypes = {
     mutation: { audioKey: string; postPhonemeLength: number };
   };
 
+  SET_MORPHING_INFO: {
+    mutation: {
+      audioKey: string;
+      morphingInfo: MorphingInfo | undefined;
+    };
+  };
+
+  MORPHING_SUPPORTED_ENGINES: {
+    getter: string[];
+  };
+
+  VALID_MOPHING_INFO: {
+    getter(audioItem: AudioItem): boolean;
+  };
+
   SET_AUDIO_QUERY: {
     mutation: { audioKey: string; audioQuery: AudioQuery };
     action(payload: { audioKey: string; audioQuery: AudioQuery }): void;
@@ -343,11 +360,11 @@ export type AudioStoreTypes = {
   };
 
   GENERATE_AUDIO: {
-    action(payload: { audioKey: string }): Promise<Blob | null>;
+    action(payload: { audioKey: string }): Promise<Blob>;
   };
 
   GENERATE_AUDIO_FROM_AUDIO_ITEM: {
-    action(payload: { audioItem: AudioItem }): Blob | null;
+    action(payload: { audioItem: AudioItem }): Blob;
   };
 
   CONNECT_AUDIO: {
@@ -581,6 +598,17 @@ export type AudioCommandStoreTypes = {
     action(payload: { audioKey: string; postPhonemeLength: number }): void;
   };
 
+  COMMAND_SET_MORPHING_INFO: {
+    mutation: {
+      audioKey: string;
+      morphingInfo: MorphingInfo | undefined;
+    };
+    action(payload: {
+      audioKey: string;
+      morphingInfo: MorphingInfo | undefined;
+    }): void;
+  };
+
   COMMAND_SET_AUDIO_PRESET: {
     mutation: {
       audioKey: string;
diff --git a/src/type/preload.ts b/src/type/preload.ts
index 2cadf7463a..38b9768284 100644
--- a/src/type/preload.ts
+++ b/src/type/preload.ts
@@ -287,6 +287,14 @@ export type Preset = {
   volumeScale: number;
   prePhonemeLength: number;
   postPhonemeLength: number;
+  morphingInfo?: MorphingInfo;
+};
+
+export type MorphingInfo = {
+  rate: number;
+  targetEngineId: string;
+  targetSpeakerId: string;
+  targetStyleId: number;
 };
 
 export type PresetConfig = {
@@ -390,6 +398,7 @@ export type ThemeSetting = {
 export type ExperimentalSetting = {
   enablePreset: boolean;
   enableInterrogativeUpspeak: boolean;
+  enableMorphing: boolean;
 };
 
 export const splitterPositionSchema = z.object({
@@ -448,6 +457,14 @@ export const electronStoreSchema = z
               volumeScale: z.number(),
               prePhonemeLength: z.number(),
               postPhonemeLength: z.number(),
+              morphingInfo: z
+                .object({
+                  rate: z.number(),
+                  targetEngineId: z.string().uuid(),
+                  targetSpeakerId: z.string().uuid(),
+                  targetStyleId: z.number(),
+                })
+                .optional(),
             })
           )
           .default({}),
@@ -460,6 +477,7 @@ export const electronStoreSchema = z
       .object({
         enablePreset: z.boolean().default(false),
         enableInterrogativeUpspeak: z.boolean().default(false),
+        enableMorphing: z.boolean().default(false),
       })
       .passthrough()
       .default({}),
diff --git a/tests/unit/store/Vuex.spec.ts b/tests/unit/store/Vuex.spec.ts
index 4b89c8e28b..45dda25715 100644
--- a/tests/unit/store/Vuex.spec.ts
+++ b/tests/unit/store/Vuex.spec.ts
@@ -114,6 +114,7 @@ describe("store/vuex.js test", () => {
         experimentalSetting: {
           enablePreset: false,
           enableInterrogativeUpspeak: false,
+          enableMorphing: false,
         },
         splitTextWhenPaste: "PERIOD_AND_NEW_LINE",
         splitterPosition: {