diff --git a/src/components/CharacterButton.vue b/src/components/CharacterButton.vue
index ca4f421eea..78c99984e9 100644
--- a/src/components/CharacterButton.vue
+++ b/src/components/CharacterButton.vue
@@ -184,7 +184,7 @@
 <script lang="ts">
 import { base64ImageToUri } from "@/helpers/imageHelper";
 import { useStore } from "@/store";
-import { CharacterInfo, Voice } from "@/type/preload";
+import { CharacterInfo, SpeakerId, Voice } from "@/type/preload";
 import { debounce } from "quasar";
 import { computed, defineComponent, PropType, ref } from "vue";
 
@@ -256,7 +256,7 @@ export default defineComponent({
       )
     );
 
-    const getDefaultStyle = (speakerUuid: string) => {
+    const getDefaultStyle = (speakerUuid: SpeakerId) => {
       // FIXME: 同一キャラが複数エンジンにまたがっているとき、順番が先のエンジンが必ず選択される
       const characterInfo = props.characterInfos.find(
         (info) => info.metas.speakerUuid === speakerUuid
@@ -276,7 +276,7 @@ export default defineComponent({
       return defaultStyle;
     };
 
-    const onSelectSpeaker = (speakerUuid: string) => {
+    const onSelectSpeaker = (speakerUuid: SpeakerId) => {
       const style = getDefaultStyle(speakerUuid);
       emit("update:selectedVoice", {
         engineId: style.engineId,
diff --git a/src/components/CharacterOrderDialog.vue b/src/components/CharacterOrderDialog.vue
index 78dafa71a6..713158354c 100644
--- a/src/components/CharacterOrderDialog.vue
+++ b/src/components/CharacterOrderDialog.vue
@@ -197,7 +197,7 @@
 import { defineComponent, computed, ref, PropType, watch } from "vue";
 import draggable from "vuedraggable";
 import { useStore } from "@/store";
-import { CharacterInfo, StyleInfo } from "@/type/preload";
+import { CharacterInfo, SpeakerId, StyleInfo } from "@/type/preload";
 
 export default defineComponent({
   name: "CharacterOrderDialog",
@@ -233,14 +233,14 @@ export default defineComponent({
     });
 
     // 新しいキャラクター
-    const newCharacters = ref<string[]>([]);
+    const newCharacters = ref<SpeakerId[]>([]);
     const hasNewCharacter = computed(() => newCharacters.value.length > 0);
 
     // サンプルボイス一覧のキャラクター順番
-    const sampleCharacterOrder = ref<string[]>([]);
+    const sampleCharacterOrder = ref<SpeakerId[]>([]);
 
     // 選択中のスタイル
-    const selectedStyleIndexes = ref<Record<string, number>>({});
+    const selectedStyleIndexes = ref<Record<SpeakerId, number>>({});
     const selectedStyles = computed(() => {
       const map: { [key: string]: StyleInfo } = {};
       props.characterInfos.forEach((characterInfo) => {
@@ -254,7 +254,7 @@ export default defineComponent({
 
     // 選択中のキャラクター
     const selectedCharacter = ref(props.characterInfos[0].metas.speakerUuid);
-    const selectCharacter = (speakerUuid: string) => {
+    const selectCharacter = (speakerUuid: SpeakerId) => {
       selectedCharacter.value = speakerUuid;
     };
 
@@ -314,14 +314,14 @@ export default defineComponent({
 
     // 音声再生
     const playing =
-      ref<{ speakerUuid: string; styleId: number; index: number }>();
+      ref<{ speakerUuid: SpeakerId; styleId: number; index: number }>();
 
     const audio = new Audio();
     audio.volume = 0.5;
     audio.onended = () => stop();
 
     const play = (
-      speakerUuid: string,
+      speakerUuid: SpeakerId,
       { styleId, voiceSamplePaths }: StyleInfo,
       index: number
     ) => {
@@ -341,7 +341,7 @@ export default defineComponent({
 
     // 再生していたら停止、再生していなかったら再生
     const togglePlayOrStop = (
-      speakerUuid: string,
+      speakerUuid: SpeakerId,
       styleInfo: StyleInfo,
       index: number
     ) => {
@@ -358,7 +358,7 @@ export default defineComponent({
     };
 
     // スタイル番号をずらす
-    const rollStyleIndex = (speakerUuid: string, diff: number) => {
+    const rollStyleIndex = (speakerUuid: SpeakerId, diff: number) => {
       // 0 <= index <= length に収める
       const length = characterInfosMap.value[speakerUuid].metas.styles.length;
       const selectedStyleIndex: number | undefined =
diff --git a/src/components/DefaultStyleListDialog.vue b/src/components/DefaultStyleListDialog.vue
index 6f6a77d015..d612311d24 100644
--- a/src/components/DefaultStyleListDialog.vue
+++ b/src/components/DefaultStyleListDialog.vue
@@ -99,7 +99,7 @@
 <script setup lang="ts">
 import { computed, ref, watch } from "vue";
 import { useStore } from "@/store";
-import { CharacterInfo, StyleInfo } from "@/type/preload";
+import { CharacterInfo, SpeakerId, StyleInfo } from "@/type/preload";
 import DefaultStyleSelectDialog from "@/components/DefaultStyleSelectDialog.vue";
 
 const props =
@@ -131,7 +131,7 @@ const selectedCharacterInfo = computed(() => {
 });
 
 const characterInfosMap = computed(() => {
-  const map: { [key: string]: CharacterInfo } = {};
+  const map: { [key: SpeakerId]: CharacterInfo } = {};
   props.characterInfos.forEach((characterInfo) => {
     map[characterInfo.metas.speakerUuid] = characterInfo;
   });
@@ -142,7 +142,7 @@ const characterInfosMap = computed(() => {
 const speakerWithMultipleStyles = ref<CharacterInfo[]>([]);
 
 // 選択中のスタイル
-const selectedStyleIndexes = ref<Record<string, number>>({});
+const selectedStyleIndexes = ref<Record<SpeakerId, number>>({});
 const selectedStyles = computed(() => {
   const map: { [key: string]: StyleInfo } = {};
   props.characterInfos.forEach((characterInfo) => {
@@ -185,14 +185,18 @@ const closeDialog = () => {
   store.dispatch(
     "SET_DEFAULT_STYLE_IDS",
     Object.entries(selectedStyleIndexes.value).map(
-      ([speakerUuid, styleIndex]) => ({
-        speakerUuid,
-        defaultStyleId:
-          characterInfosMap.value[speakerUuid].metas.styles[styleIndex].styleId,
-        engineId:
-          characterInfosMap.value[speakerUuid].metas.styles[styleIndex]
-            .engineId,
-      })
+      ([speakerUuidStr, styleIndex]) => {
+        const speakerUuid = SpeakerId(speakerUuidStr);
+        return {
+          speakerUuid,
+          defaultStyleId:
+            characterInfosMap.value[speakerUuid].metas.styles[styleIndex]
+              .styleId,
+          engineId:
+            characterInfosMap.value[speakerUuid].metas.styles[styleIndex]
+              .engineId,
+        };
+      }
     )
   );
   stop();
diff --git a/src/components/DefaultStyleSelectDialog.vue b/src/components/DefaultStyleSelectDialog.vue
index b9e82a3439..2906f73cf3 100644
--- a/src/components/DefaultStyleSelectDialog.vue
+++ b/src/components/DefaultStyleSelectDialog.vue
@@ -123,7 +123,12 @@
 <script setup lang="ts">
 import { computed, ref, watch } from "vue";
 import { useStore } from "@/store";
-import { CharacterInfo, DefaultStyleId, StyleInfo } from "@/type/preload";
+import {
+  CharacterInfo,
+  DefaultStyleId,
+  SpeakerId,
+  StyleInfo,
+} from "@/type/preload";
 
 const props =
   defineProps<{
@@ -188,7 +193,7 @@ audio.volume = 0.5;
 audio.onended = () => stop();
 
 const play = (
-  speakerUuid: string,
+  speakerUuid: SpeakerId,
   { styleId, voiceSamplePaths }: StyleInfo,
   index: number
 ) => {
diff --git a/src/store/audio.ts b/src/store/audio.ts
index 33b1241477..3563ebda14 100644
--- a/src/store/audio.ts
+++ b/src/store/audio.ts
@@ -20,6 +20,7 @@ import {
   EngineId,
   MoraDataType,
   MorphingInfo,
+  SpeakerId,
   StyleInfo,
   Voice,
   WriteFileErrorResult,
@@ -283,7 +284,7 @@ export const audioStore = createPartialStore<AudioStoreTypes>({
         const characterInfo: CharacterInfo = {
           portraitPath: base64ImageToUri(speakerInfo.portrait),
           metas: {
-            speakerUuid: speaker.speakerUuid,
+            speakerUuid: SpeakerId(speaker.speakerUuid),
             speakerName: speaker.name,
             styles,
             policy: speakerInfo.policy,
diff --git a/src/store/project.ts b/src/store/project.ts
index 642466e406..0aa1bf05c8 100755
--- a/src/store/project.ts
+++ b/src/store/project.ts
@@ -6,7 +6,7 @@ import { createPartialStore } from "./vuex";
 
 import { AccentPhrase } from "@/openapi";
 import { z } from "zod";
-import { EngineId, engineIdSchema } from "@/type/preload";
+import { EngineId, engineIdSchema, speakerIdSchema } from "@/type/preload";
 
 const DEFAULT_SAMPLING_RATE = 24000;
 
@@ -473,7 +473,7 @@ const audioQuerySchema = z.object({
 const morphingInfoSchema = z.object({
   rate: z.number(),
   targetEngineId: engineIdSchema,
-  targetSpeakerId: z.string(),
+  targetSpeakerId: speakerIdSchema,
   targetStyleId: z.number(),
 });
 
@@ -481,7 +481,7 @@ const audioItemSchema = z.object({
   text: z.string(),
   voice: z.object({
     engineId: engineIdSchema,
-    speakerId: z.string().uuid(),
+    speakerId: speakerIdSchema,
     styleId: z.number(),
   }),
   query: audioQuerySchema.optional(),
diff --git a/src/store/type.ts b/src/store/type.ts
index 076590511b..390e41dcf6 100644
--- a/src/store/type.ts
+++ b/src/store/type.ts
@@ -44,6 +44,7 @@ import {
   EngineSetting,
   Voice,
   EngineId,
+  SpeakerId,
 } from "@/type/preload";
 import { IEngineConnectorFactory } from "@/infrastructures/EngineConnector";
 import { QVueGlobals } from "quasar";
@@ -112,7 +113,7 @@ export type QuasarDialog = QVueGlobals["dialog"];
 
 export type AudioStoreState = {
   characterInfos: Record<EngineId, CharacterInfo[]>;
-  morphableTargetsInfo: Record<string, MorphableTargetInfoTable>;
+  morphableTargetsInfo: Record<EngineId, MorphableTargetInfoTable>;
   audioKeyInitializingSpeaker?: string;
   audioItems: Record<string, AudioItem>;
   audioKeys: string[];
@@ -823,13 +824,13 @@ export type EngineStoreTypes = {
 
 export type IndexStoreState = {
   defaultStyleIds: DefaultStyleId[];
-  userCharacterOrder: string[];
+  userCharacterOrder: SpeakerId[];
   isMultiEngineOffMode: boolean;
 };
 
 export type IndexStoreTypes = {
   GET_ALL_CHARACTER_INFOS: {
-    getter: Map<string, CharacterInfo>;
+    getter: Map<SpeakerId, CharacterInfo>;
   };
 
   GET_ORDERED_ALL_CHARACTER_INFOS: {
@@ -882,12 +883,12 @@ export type IndexStoreTypes = {
   };
 
   SET_USER_CHARACTER_ORDER: {
-    mutation: { userCharacterOrder: string[] };
-    action(payload: string[]): void;
+    mutation: { userCharacterOrder: SpeakerId[] };
+    action(payload: SpeakerId[]): void;
   };
 
   GET_NEW_CHARACTERS: {
-    action(): string[];
+    action(): SpeakerId[];
   };
 
   LOG_ERROR: {
diff --git a/src/type/preload.ts b/src/type/preload.ts
index b17979537c..6739612f71 100644
--- a/src/type/preload.ts
+++ b/src/type/preload.ts
@@ -8,6 +8,10 @@ export const engineIdSchema = z.string().uuid().brand<"EngineId">();
 export type EngineId = z.infer<typeof engineIdSchema>;
 export const EngineId = (id: string): EngineId => engineIdSchema.parse(id);
 
+export const speakerIdSchema = z.string().uuid().brand<"SpeakerId">();
+export type SpeakerId = z.infer<typeof speakerIdSchema>;
+export const SpeakerId = (id: string): SpeakerId => speakerIdSchema.parse(id);
+
 // ホットキーを追加したときは設定のマイグレーションが必要
 export const defaultHotkeySettings: HotkeySetting[] = [
   {
@@ -214,14 +218,14 @@ export type StyleInfo = {
 
 export type MetasJson = {
   speakerName: string;
-  speakerUuid: string;
+  speakerUuid: SpeakerId;
   styles: Pick<StyleInfo, "styleName" | "styleId">[];
 };
 
 export type CharacterInfo = {
   portraitPath: string;
   metas: {
-    speakerUuid: string;
+    speakerUuid: SpeakerId;
     speakerName: string;
     styles: StyleInfo[];
     policy: string;
@@ -236,7 +240,7 @@ export type UpdateInfo = {
 
 export type Voice = {
   engineId: EngineId;
-  speakerId: string;
+  speakerId: SpeakerId;
   styleId: number;
 };
 
@@ -281,7 +285,7 @@ export type EngineSetting = z.infer<typeof engineSettingSchema>;
 
 export type DefaultStyleId = {
   engineId: EngineId;
-  speakerUuid: string;
+  speakerUuid: SpeakerId;
   defaultStyleId: number;
 };
 
@@ -332,7 +336,7 @@ export type Preset = {
 export type MorphingInfo = {
   rate: number;
   targetEngineId: EngineId;
-  targetSpeakerId: string;
+  targetSpeakerId: SpeakerId;
   targetStyleId: number;
 };
 
@@ -492,14 +496,14 @@ export const electronStoreSchema = z
       .array()
       .default(defaultToolbarButtonSetting),
     engineSettings: z.record(engineIdSchema, engineSettingSchema).default({}),
-    userCharacterOrder: z.string().array().default([]),
+    userCharacterOrder: speakerIdSchema.array().default([]),
     defaultStyleIds: z
       .object({
         // FIXME: マイグレーション前にバリテーションされてしまう問題に対処したら.or(z.literal)を外す
         engineId: engineIdSchema
           .or(z.literal(EngineId("00000000-0000-0000-0000-000000000000")))
           .default(EngineId("00000000-0000-0000-0000-000000000000")),
-        speakerUuid: z.string().uuid(),
+        speakerUuid: speakerIdSchema,
         defaultStyleId: z.number(),
       })
       .passthrough()
@@ -523,7 +527,7 @@ export const electronStoreSchema = z
                   .object({
                     rate: z.number(),
                     targetEngineId: engineIdSchema,
-                    targetSpeakerId: z.string().uuid(),
+                    targetSpeakerId: speakerIdSchema,
                     targetStyleId: z.number(),
                   })
                   .passthrough()