diff --git a/packages/backend/src/core/SystemAccountService.ts b/packages/backend/src/core/SystemAccountService.ts
index cd91355d06..4805847788 100644
--- a/packages/backend/src/core/SystemAccountService.ts
+++ b/packages/backend/src/core/SystemAccountService.ts
@@ -66,7 +66,7 @@ export class SystemAccountService {
 			return systemAccount.user as MiLocalUser;
 		} else {
 			const created = await this.createCorrespondingUser(type, {
-				username: `system.${type}`,
+				username: `system.${type}`, // NOTE: (できれば避けたいが)system.から始まるかどうかでシステムアカウントかどうかを判定している処理もあるので変えないように
 				name: this.meta.name,
 			});
 			this.cache.set(type, created);
diff --git a/packages/frontend/src/pages/admin-user.vue b/packages/frontend/src/pages/admin-user.vue
index fa08c213e2..1220b2f6aa 100644
--- a/packages/frontend/src/pages/admin-user.vue
+++ b/packages/frontend/src/pages/admin-user.vue
@@ -22,7 +22,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 					</div>
 				</div>
 
-				<MkInfo v-if="['instance.actor', 'relay.actor'].includes(user.username)">{{ i18n.ts.isSystemAccount }}</MkInfo>
+				<MkInfo v-if="user.host == null && user.username.startsWith('system.')">{{ i18n.ts.isSystemAccount }}</MkInfo>
 
 				<FormLink v-if="user.host" :to="`/instance-info/${user.host}`">{{ i18n.ts.instanceInfo }}</FormLink>
 
diff --git a/packages/frontend/src/pages/user/home.vue b/packages/frontend/src/pages/user/home.vue
index a6a49f0ab9..c2a59307ee 100644
--- a/packages/frontend/src/pages/user/home.vue
+++ b/packages/frontend/src/pages/user/home.vue
@@ -61,6 +61,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 							</MkA>
 						</span>
 					</div>
+					<div v-if="user.host == null && user.username.startsWith('system.')" class="isSystemAccount">
+						<MkInfo>{{ i18n.ts.isSystemAccount }}</MkInfo>
+					</div>
 					<div v-if="iAmModerator" class="moderationNote">
 						<MkTextarea v-if="editModerationNote || (moderationNote != null && moderationNote !== '')" v-model="moderationNote" manualSave>
 							<template #label>{{ i18n.ts.moderationNote }}</template>