diff --git a/packages/frontend/src/pages/qr.read.vue b/packages/frontend/src/pages/qr.read.vue
index 91ea8c147b..3ff63016a2 100644
--- a/packages/frontend/src/pages/qr.read.vue
+++ b/packages/frontend/src/pages/qr.read.vue
@@ -57,7 +57,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import QrScanner from 'qr-scanner';
-import { onMounted, onUnmounted, ref, shallowRef, watch } from 'vue';
+import { onActivated, onDeactivated, onMounted, onUnmounted, ref, shallowRef, watch } from 'vue';
 import * as misskey from 'misskey-js';
 import { getScrollContainer } from '@@/js/scroll.js';
 import type { ApShowResponse } from 'misskey-js/entities.js';
@@ -206,12 +206,20 @@ async function startQr() {
 	qrStarted.value = true;
 }
 
-async function stopQr() {
+function stopQr() {
 	if (!scannerInstance.value) return;
-	await scannerInstance.value.stop();
+	scannerInstance.value.stop();
 	qrStarted.value = false;
 }
 
+onActivated(() => {
+	startQr;
+});
+
+onDeactivated(() => {
+	stopQr;
+});
+
 const alertLock = ref(false);
 
 onMounted(() => {