diff --git a/src/features/messages/speakCharacter.ts b/src/features/messages/speakCharacter.ts
index 9a7fc42d..78c3d8ae 100644
--- a/src/features/messages/speakCharacter.ts
+++ b/src/features/messages/speakCharacter.ts
@@ -1,7 +1,6 @@
 import homeStore from '@/features/stores/home'
 import settingsStore from '@/features/stores/settings'
 import englishToJapanese from '@/utils/englishToJapanese.json'
-import { wait } from '@/utils/wait'
 import { Talk } from './messages'
 import { synthesizeStyleBertVITS2Api } from './synthesizeStyleBertVITS2'
 import { synthesizeVoiceKoeiromapApi } from './synthesizeVoiceKoeiromap'
@@ -48,9 +47,6 @@ function preprocessMessage(
 }
 
 const createSpeakCharacter = () => {
-  let lastTime = 0
-  let prevFetchPromise: Promise<unknown> = Promise.resolve()
-
   return (talk: Talk, onStart?: () => void, onComplete?: () => void) => {
     const ss = settingsStore.getState()
     onStart?.()
@@ -66,117 +62,110 @@ const createSpeakCharacter = () => {
 
     let isNeedDecode = true
 
-    const fetchPromise = prevFetchPromise.then(async () => {
-      const now = Date.now()
-      if (now - lastTime < 1000) {
-        await wait(1000 - (now - lastTime))
-      }
-
-      let buffer
+    // audioBufferのフェッチを開始
+    const audioBufferPromise: Promise<ArrayBuffer | null> = (async () => {
       try {
-        if (talk.message == '' && talk.buffer) {
-          buffer = talk.buffer
+        if (talk.message === '' && talk.buffer) {
           isNeedDecode = false
+          return talk.buffer
         } else if (ss.audioMode) {
-          buffer = null
-        } else if (ss.selectVoice == 'koeiromap') {
-          buffer = await synthesizeVoiceKoeiromapApi(
-            talk,
-            ss.koeiromapKey,
-            ss.koeiroParam
-          )
-        } else if (ss.selectVoice == 'voicevox') {
-          buffer = await synthesizeVoiceVoicevoxApi(
-            talk,
-            ss.voicevoxSpeaker,
-            ss.voicevoxSpeed,
-            ss.voicevoxPitch,
-            ss.voicevoxIntonation
-          )
-        } else if (ss.selectVoice == 'google') {
-          buffer = await synthesizeVoiceGoogleApi(
-            talk,
-            ss.googleTtsType,
-            ss.selectLanguage
-          )
-        } else if (ss.selectVoice == 'stylebertvits2') {
-          buffer = await synthesizeStyleBertVITS2Api(
-            talk,
-            ss.stylebertvits2ServerUrl,
-            ss.stylebertvits2ApiKey,
-            ss.stylebertvits2ModelId,
-            ss.stylebertvits2Style,
-            ss.stylebertvits2SdpRatio,
-            ss.stylebertvits2Length,
-            ss.selectLanguage
-          )
-        } else if (ss.selectVoice == 'aivis_speech') {
-          buffer = await synthesizeVoiceAivisSpeechApi(
-            talk,
-            ss.aivisSpeechSpeaker,
-            ss.aivisSpeechSpeed,
-            ss.aivisSpeechPitch,
-            ss.aivisSpeechIntonation
-          )
-        } else if (ss.selectVoice == 'gsvitts') {
-          buffer = await synthesizeVoiceGSVIApi(
-            talk,
-            ss.gsviTtsServerUrl,
-            ss.gsviTtsModelId,
-            ss.gsviTtsBatchSize,
-            ss.gsviTtsSpeechRate
-          )
-        } else if (ss.selectVoice == 'elevenlabs') {
-          buffer = await synthesizeVoiceElevenlabsApi(
-            talk,
-            ss.elevenlabsApiKey,
-            ss.elevenlabsVoiceId,
-            ss.selectLanguage
-          )
-        } else if (ss.selectVoice == 'openai') {
-          buffer = await synthesizeVoiceOpenAIApi(
-            talk,
-            ss.openaiTTSKey || ss.openaiKey,
-            ss.openaiTTSVoice,
-            ss.openaiTTSModel,
-            ss.openaiTTSSpeed
-          )
-        } else if (ss.selectVoice == 'azure') {
-          buffer = await synthesizeVoiceAzureOpenAIApi(
-            talk,
-            ss.azureTTSKey || ss.azureKey,
-            ss.azureTTSEndpoint || ss.azureEndpoint,
-            ss.openaiTTSVoice,
-            ss.openaiTTSSpeed
-          )
-        } else if (ss.selectVoice == 'nijivoice') {
-          buffer = await synthesizeVoiceNijivoiceApi(
-            talk,
-            ss.nijivoiceApiKey,
-            ss.nijivoiceActorId,
-            ss.nijivoiceSpeed
-          )
+          return null
+        }
+
+        // 選択されたボイスに応じたTTS APIを呼び出す
+        switch (ss.selectVoice) {
+          case 'koeiromap':
+            return await synthesizeVoiceKoeiromapApi(
+              talk,
+              ss.koeiromapKey,
+              ss.koeiroParam
+            )
+          case 'voicevox':
+            return await synthesizeVoiceVoicevoxApi(
+              talk,
+              ss.voicevoxSpeaker,
+              ss.voicevoxSpeed,
+              ss.voicevoxPitch,
+              ss.voicevoxIntonation
+            )
+          case 'google':
+            return await synthesizeVoiceGoogleApi(
+              talk,
+              ss.googleTtsType,
+              ss.selectLanguage
+            )
+          case 'stylebertvits2':
+            return await synthesizeStyleBertVITS2Api(
+              talk,
+              ss.stylebertvits2ServerUrl,
+              ss.stylebertvits2ApiKey,
+              ss.stylebertvits2ModelId,
+              ss.stylebertvits2Style,
+              ss.stylebertvits2SdpRatio,
+              ss.stylebertvits2Length,
+              ss.selectLanguage
+            )
+          case 'aivis_speech':
+            return await synthesizeVoiceAivisSpeechApi(
+              talk,
+              ss.aivisSpeechSpeaker,
+              ss.aivisSpeechSpeed,
+              ss.aivisSpeechPitch,
+              ss.aivisSpeechIntonation
+            )
+          case 'gsvitts':
+            return await synthesizeVoiceGSVIApi(
+              talk,
+              ss.gsviTtsServerUrl,
+              ss.gsviTtsModelId,
+              ss.gsviTtsBatchSize,
+              ss.gsviTtsSpeechRate
+            )
+          case 'elevenlabs':
+            return await synthesizeVoiceElevenlabsApi(
+              talk,
+              ss.elevenlabsApiKey,
+              ss.elevenlabsVoiceId,
+              ss.selectLanguage
+            )
+          case 'openai':
+            return await synthesizeVoiceOpenAIApi(
+              talk,
+              ss.openaiTTSKey || ss.openaiKey,
+              ss.openaiTTSVoice,
+              ss.openaiTTSModel,
+              ss.openaiTTSSpeed
+            )
+          case 'azure':
+            return await synthesizeVoiceAzureOpenAIApi(
+              talk,
+              ss.azureTTSKey || ss.azureKey,
+              ss.azureTTSEndpoint || ss.azureEndpoint,
+              ss.openaiTTSVoice,
+              ss.openaiTTSSpeed
+            )
+          case 'nijivoice':
+            return await synthesizeVoiceNijivoiceApi(
+              talk,
+              ss.nijivoiceApiKey,
+              ss.nijivoiceActorId,
+              ss.nijivoiceSpeed
+            )
+          default:
+            throw new Error('Unsupported voice type')
         }
       } catch (error) {
         handleTTSError(error, ss.selectVoice)
         return null
       }
-      lastTime = Date.now()
-      return buffer
-    })
-
-    prevFetchPromise = fetchPromise
-
-    // キューを使用した処理に変更
-    fetchPromise.then((audioBuffer) => {
-      if (!audioBuffer) return
-
-      speakQueue.addTask({
-        audioBuffer,
-        talk,
-        isNeedDecode,
-        onComplete,
-      })
+    })()
+
+    // タスクをSpeakQueueに追加
+    speakQueue.addTask({
+      audioBufferPromise,
+      talk,
+      isNeedDecode,
+      onComplete,
     })
   }
 }
diff --git a/src/features/messages/speakQueue.ts b/src/features/messages/speakQueue.ts
index fbc18b93..a7aa26b0 100644
--- a/src/features/messages/speakQueue.ts
+++ b/src/features/messages/speakQueue.ts
@@ -1,8 +1,8 @@
 import { Talk } from './messages'
 import homeStore from '@/features/stores/home'
 
-type SpeakTask = {
-  audioBuffer: ArrayBuffer
+type SpeakTaskWithPromise = {
+  audioBufferPromise: Promise<ArrayBuffer | null>
   talk: Talk
   isNeedDecode: boolean
   onComplete?: () => void
@@ -10,12 +10,12 @@ type SpeakTask = {
 
 export class SpeakQueue {
   private static readonly QUEUE_CHECK_DELAY = 1500
-  private queue: SpeakTask[] = []
+  private queue: SpeakTaskWithPromise[] = []
   private isProcessing = false
 
-  async addTask(task: SpeakTask) {
+  addTask(task: SpeakTaskWithPromise) {
     this.queue.push(task)
-    await this.processQueue()
+    this.processQueue()
   }
 
   private async processQueue() {
@@ -27,9 +27,15 @@ export class SpeakQueue {
       const task = this.queue.shift()
       if (task) {
         try {
-          const { audioBuffer, talk, isNeedDecode, onComplete } = task
-          await hs.viewer.model?.speak(audioBuffer, talk, isNeedDecode)
-          onComplete?.()
+          const audioBuffer = await task.audioBufferPromise
+          if (audioBuffer) {
+            await hs.viewer.model?.speak(
+              audioBuffer,
+              task.talk,
+              task.isNeedDecode
+            )
+            task.onComplete?.()
+          }
         } catch (error) {
           console.error(
             'An error occurred while processing the speech synthesis task:',