diff --git a/packages/client/package.json b/packages/client/package.json
index e533e1fb8..0a9473a54 100644
--- a/packages/client/package.json
+++ b/packages/client/package.json
@@ -31,6 +31,7 @@
 		"css-loader": "6.7.1",
 		"cssnano": "5.1.7",
 		"date-fns": "2.28.0",
+		"deepcopy": "2.1.0",
 		"escape-regexp": "0.0.1",
 		"eslint": "8.14.0",
 		"eslint-plugin-vue": "8.7.1",
diff --git a/packages/client/src/pizzax.ts b/packages/client/src/pizzax.ts
index 338898005..389554247 100644
--- a/packages/client/src/pizzax.ts
+++ b/packages/client/src/pizzax.ts
@@ -1,10 +1,11 @@
-import { onUnmounted, Ref, ref, toRaw, watch } from 'vue';
+import { onUnmounted, Ref, ref, watch } from 'vue';
 import { $i } from './account';
 import { api } from './os';
 import { get, set } from './scripts/idb-proxy';
 import { defaultStore } from './store';
 import { stream } from './stream';
 import { BroadcastChannel } from 'broadcast-channel';
+import deepcopy from 'deepcopy';
 
 type StateDef = Record<string, {
 	where: 'account' | 'device' | 'deviceAccount';
@@ -153,7 +154,7 @@ export class Storage<T extends StateDef> {
 	public set<K extends keyof T>(key: K, value: T[K]['default']): Promise<void> {
 		// IndexedDBやBroadcastChannelで扱うために単純なオブジェクトにする
 		// (JSON.parse(JSON.stringify(value))の代わり)
-		const rawValue = structuredClone(toRaw(value));
+		const rawValue = deepcopy(value);
 
 		if (_DEV_) console.log('set', key, rawValue, value);
 
diff --git a/packages/client/yarn.lock b/packages/client/yarn.lock
index 05e175544..9b10508a5 100644
--- a/packages/client/yarn.lock
+++ b/packages/client/yarn.lock
@@ -1954,6 +1954,13 @@ deep-is@^0.1.3:
   resolved "https://registry.yarnpkg.com/deep-is/-/deep-is-0.1.3.tgz#b369d6fb5dbc13eecf524f91b070feedc357cf34"
   integrity sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ=
 
+deepcopy@2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/deepcopy/-/deepcopy-2.1.0.tgz#2deb0dd52d079c2ecb7924b640a7c3abd4db1d6d"
+  integrity sha512-8cZeTb1ZKC3bdSCP6XOM1IsTczIO73fdqtwa2B0N15eAz7gmyhQo+mc5gnFuulsgN3vIQYmTgbmQVKalH1dKvQ==
+  dependencies:
+    type-detect "^4.0.8"
+
 define-properties@^1.1.2, define-properties@^1.1.3:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/define-properties/-/define-properties-1.1.3.tgz#cf88da6cbee26fe6db7094f61d870cbd84cee9f1"
@@ -5579,6 +5586,11 @@ type-check@^0.4.0, type-check@~0.4.0:
   dependencies:
     prelude-ls "^1.2.1"
 
+type-detect@^4.0.8:
+  version "4.0.8"
+  resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
+  integrity sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==
+
 type-fest@^0.20.2:
   version "0.20.2"
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.20.2.tgz#1bf207f4b28f91583666cb5fbd327887301cd5f4"