diff --git a/CHANGELOG.md b/CHANGELOG.md
index e1de194da1..31850e1d53 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@
 ## 202x.x.x (unreleased)
 
 ### General
+- Enhance: サーバーごとにモデレーションノートを残せるように
 
 ### Client
 - Enhance: ノート作成画面のファイル添付メニューの区切り線の位置を調整
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 1bc99ab849..d483fea837 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -9172,7 +9172,7 @@ export interface Locale extends ILocale {
          */
         "updateServerSettings": string;
         /**
-         * モデレーションノート更新
+         * ユーザーのモデレーションノート更新
          */
         "updateUserNote": string;
         /**
@@ -9219,6 +9219,10 @@ export interface Locale extends ILocale {
          * リモートサーバーを再開
          */
         "unsuspendRemoteInstance": string;
+        /**
+         * リモートサーバーのモデレーションノート更新
+         */
+        "updateRemoteInstanceNote": string;
         /**
          * ファイルをセンシティブ付与
          */
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 5993ec80d0..7e16619fc7 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -2434,7 +2434,7 @@ _moderationLogTypes:
   updateCustomEmoji: "カスタム絵文字更新"
   deleteCustomEmoji: "カスタム絵文字削除"
   updateServerSettings: "サーバー設定更新"
-  updateUserNote: "モデレーションノート更新"
+  updateUserNote: "ユーザーのモデレーションノート更新"
   deleteDriveFile: "ファイルを削除"
   deleteNote: "ノートを削除"
   createGlobalAnnouncement: "全体のお知らせを作成"
@@ -2446,6 +2446,7 @@ _moderationLogTypes:
   resetPassword: "パスワードをリセット"
   suspendRemoteInstance: "リモートサーバーを停止"
   unsuspendRemoteInstance: "リモートサーバーを再開"
+  updateRemoteInstanceNote: "リモートサーバーのモデレーションノート更新"
   markSensitiveDriveFile: "ファイルをセンシティブ付与"
   unmarkSensitiveDriveFile: "ファイルをセンシティブ解除"
   resolveAbuseReport: "通報を解決"
diff --git a/packages/backend/migration/1708399372194-per-instance-mod-note.js b/packages/backend/migration/1708399372194-per-instance-mod-note.js
new file mode 100644
index 0000000000..339a4d7af9
--- /dev/null
+++ b/packages/backend/migration/1708399372194-per-instance-mod-note.js
@@ -0,0 +1,16 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export class PerInstanceModNote1708399372194 {
+    name = 'PerInstanceModNote1708399372194'
+
+    async up(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "instance" ADD "moderationNote" character varying(16384) NOT NULL DEFAULT ''`);
+    }
+
+    async down(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "instance" DROP COLUMN "moderationNote"`);
+    }
+}
diff --git a/packages/backend/src/core/entities/InstanceEntityService.ts b/packages/backend/src/core/entities/InstanceEntityService.ts
index 9287c98003..e46bd8b963 100644
--- a/packages/backend/src/core/entities/InstanceEntityService.ts
+++ b/packages/backend/src/core/entities/InstanceEntityService.ts
@@ -8,12 +8,15 @@ import type { Packed } from '@/misc/json-schema.js';
 import type { MiInstance } from '@/models/Instance.js';
 import { MetaService } from '@/core/MetaService.js';
 import { bindThis } from '@/decorators.js';
-import { UtilityService } from '../UtilityService.js';
+import { UtilityService } from '@/core/UtilityService.js';
+import { RoleService } from '@/core/RoleService.js';
+import { MiUser } from '@/models/User.js';
 
 @Injectable()
 export class InstanceEntityService {
 	constructor(
 		private metaService: MetaService,
+		private roleService: RoleService,
 
 		private utilityService: UtilityService,
 	) {
@@ -22,8 +25,11 @@ export class InstanceEntityService {
 	@bindThis
 	public async pack(
 		instance: MiInstance,
+		me?: { id: MiUser['id']; } | null | undefined,
 	): Promise<Packed<'FederationInstance'>> {
 		const meta = await this.metaService.fetch();
+		const iAmModerator = me ? await this.roleService.isModerator(me as MiUser) : false;
+
 		return {
 			id: instance.id,
 			firstRetrievedAt: instance.firstRetrievedAt.toISOString(),
@@ -48,6 +54,7 @@ export class InstanceEntityService {
 			themeColor: instance.themeColor,
 			infoUpdatedAt: instance.infoUpdatedAt ? instance.infoUpdatedAt.toISOString() : null,
 			latestRequestReceivedAt: instance.latestRequestReceivedAt ? instance.latestRequestReceivedAt.toISOString() : null,
+			moderationNote: iAmModerator ? instance.moderationNote : null,
 		};
 	}
 
diff --git a/packages/backend/src/models/Instance.ts b/packages/backend/src/models/Instance.ts
index 0632ef525b..9863c9d75d 100644
--- a/packages/backend/src/models/Instance.ts
+++ b/packages/backend/src/models/Instance.ts
@@ -144,4 +144,9 @@ export class MiInstance {
 		nullable: true,
 	})
 	public infoUpdatedAt: Date | null;
+
+	@Column('varchar', {
+		length: 16384, default: '',
+	})
+	public moderationNote: string;
 }
diff --git a/packages/backend/src/models/json-schema/federation-instance.ts b/packages/backend/src/models/json-schema/federation-instance.ts
index 087a0e6967..42d98fe523 100644
--- a/packages/backend/src/models/json-schema/federation-instance.ts
+++ b/packages/backend/src/models/json-schema/federation-instance.ts
@@ -107,5 +107,9 @@ export const packedFederationInstanceSchema = {
 			optional: false, nullable: true,
 			format: 'date-time',
 		},
+		moderationNote: {
+			type: 'string',
+			optional: true, nullable: true,
+		},
 	},
 } as const;
diff --git a/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts b/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
index b989b99e47..0bcdc2a4b8 100644
--- a/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
+++ b/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
@@ -24,8 +24,9 @@ export const paramDef = {
 	properties: {
 		host: { type: 'string' },
 		isSuspended: { type: 'boolean' },
+		moderationNote: { type: 'string' },
 	},
-	required: ['host', 'isSuspended'],
+	required: ['host'],
 } as const;
 
 @Injectable()
@@ -47,9 +48,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			await this.federatedInstanceService.update(instance.id, {
 				isSuspended: ps.isSuspended,
+				moderationNote: ps.moderationNote,
 			});
 
-			if (instance.isSuspended !== ps.isSuspended) {
+			if (ps.isSuspended != null && instance.isSuspended !== ps.isSuspended) {
 				if (ps.isSuspended) {
 					this.moderationLogService.log(me, 'suspendRemoteInstance', {
 						id: instance.id,
@@ -62,6 +64,15 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 					});
 				}
 			}
+
+			if (ps.moderationNote != null && instance.moderationNote !== ps.moderationNote) {
+				this.moderationLogService.log(me, 'updateRemoteInstanceNote', {
+					id: instance.id,
+					host: instance.host,
+					before: instance.moderationNote,
+					after: ps.moderationNote,
+				});
+			}
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/federation/show-instance.ts b/packages/backend/src/server/api/endpoints/federation/show-instance.ts
index e3c598d110..2972861a4b 100644
--- a/packages/backend/src/server/api/endpoints/federation/show-instance.ts
+++ b/packages/backend/src/server/api/endpoints/federation/show-instance.ts
@@ -43,7 +43,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 			const instance = await this.instancesRepository
 				.findOneBy({ host: this.utilityService.toPuny(ps.host) });
 
-			return instance ? await this.instanceEntityService.pack(instance) : null;
+			return instance ? await this.instanceEntityService.pack(instance, me) : null;
 		});
 	}
 }
diff --git a/packages/backend/src/types.ts b/packages/backend/src/types.ts
index fdcd2c0629..506a755cc4 100644
--- a/packages/backend/src/types.ts
+++ b/packages/backend/src/types.ts
@@ -69,6 +69,7 @@ export const moderationLogTypes = [
 	'resetPassword',
 	'suspendRemoteInstance',
 	'unsuspendRemoteInstance',
+	'updateRemoteInstanceNote',
 	'markSensitiveDriveFile',
 	'unmarkSensitiveDriveFile',
 	'resolveAbuseReport',
@@ -209,6 +210,12 @@ export type ModerationLogPayloads = {
 		id: string;
 		host: string;
 	};
+	updateRemoteInstanceNote: {
+		id: string;
+		host: string;
+		before: string | null;
+		after: string | null;
+	};
 	markSensitiveDriveFile: {
 		fileId: string;
 		fileUserId: string | null;
diff --git a/packages/frontend/src/pages/admin/modlog.ModLog.vue b/packages/frontend/src/pages/admin/modlog.ModLog.vue
index 21d68331cb..e33c882721 100644
--- a/packages/frontend/src/pages/admin/modlog.ModLog.vue
+++ b/packages/frontend/src/pages/admin/modlog.ModLog.vue
@@ -110,6 +110,12 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<CodeDiff :context="5" :hideHeader="true" :oldString="JSON5.stringify(log.info.before, null, '\t')" :newString="JSON5.stringify(log.info.after, null, '\t')" language="javascript" maxHeight="300px"/>
 			</div>
 		</template>
+		<template v-else-if="log.type === 'updateRemoteInstanceNote'">
+			<div>{{ i18n.ts.user }}: {{ log.info.userId }}</div>
+			<div :class="$style.diff">
+				<CodeDiff :context="5" :hideHeader="true" :oldString="log.info.before ?? ''" :newString="log.info.after ?? ''" maxHeight="300px"/>
+			</div>
+		</template>
 
 		<details>
 			<summary>raw</summary>
diff --git a/packages/frontend/src/pages/instance-info.vue b/packages/frontend/src/pages/instance-info.vue
index 2f1557182a..cb7fe2866c 100644
--- a/packages/frontend/src/pages/instance-info.vue
+++ b/packages/frontend/src/pages/instance-info.vue
@@ -39,6 +39,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 						<MkSwitch v-model="isBlocked" :disabled="!meta || !instance" @update:modelValue="toggleBlock">{{ i18n.ts.blockThisInstance }}</MkSwitch>
 						<MkSwitch v-model="isSilenced" :disabled="!meta || !instance" @update:modelValue="toggleSilenced">{{ i18n.ts.silenceThisInstance }}</MkSwitch>
 						<MkButton @click="refreshMetadata"><i class="ti ti-refresh"></i> Refresh metadata</MkButton>
+						<MkTextarea v-model="moderationNote" manualSave>
+							<template #label>{{ i18n.ts.moderationNote }}</template>
+						</MkTextarea>
 					</div>
 				</FormSection>
 
@@ -119,7 +122,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script lang="ts" setup>
-import { ref, computed } from 'vue';
+import { ref, computed, watch } from 'vue';
 import * as Misskey from 'misskey-js';
 import MkChart from '@/components/MkChart.vue';
 import MkObjectView from '@/components/MkObjectView.vue';
@@ -141,6 +144,7 @@ import MkPagination from '@/components/MkPagination.vue';
 import MkHorizontalSwipe from '@/components/MkHorizontalSwipe.vue';
 import { getProxiedImageUrlNullable } from '@/scripts/media-proxy.js';
 import { dateString } from '@/filters/date.js';
+import MkTextarea from '@/components/MkTextarea.vue';
 
 const props = defineProps<{
 	host: string;
@@ -155,6 +159,7 @@ const suspended = ref(false);
 const isBlocked = ref(false);
 const isSilenced = ref(false);
 const faviconUrl = ref<string | null>(null);
+const moderationNote = ref('');
 
 const usersPagination = {
 	endpoint: iAmModerator ? 'admin/show-users' : 'users' as const,
@@ -167,6 +172,10 @@ const usersPagination = {
 	offsetMode: true,
 };
 
+watch(moderationNote, async () => {
+	await misskeyApi('admin/federation/update-instance', { host: instance.value.host, moderationNote: moderationNote.value });
+});
+
 async function fetch(): Promise<void> {
 	if (iAmAdmin) {
 		meta.value = await misskeyApi('admin/meta');
@@ -178,6 +187,7 @@ async function fetch(): Promise<void> {
 	isBlocked.value = instance.value?.isBlocked ?? false;
 	isSilenced.value = instance.value?.isSilenced ?? false;
 	faviconUrl.value = getProxiedImageUrlNullable(instance.value?.faviconUrl, 'preview') ?? getProxiedImageUrlNullable(instance.value?.iconUrl, 'preview');
+	moderationNote.value = instance.value?.moderationNote;
 }
 
 async function toggleBlock(): Promise<void> {
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index f362f0b34e..c2428910fa 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -2316,6 +2316,9 @@ type ModerationLog = {
 } | {
     type: 'unsuspendRemoteInstance';
     info: ModerationLogPayloads['unsuspendRemoteInstance'];
+} | {
+    type: 'updateRemoteInstanceNote';
+    info: ModerationLogPayloads['updateRemoteInstanceNote'];
 } | {
     type: 'markSensitiveDriveFile';
     info: ModerationLogPayloads['markSensitiveDriveFile'];
@@ -2355,7 +2358,7 @@ type ModerationLog = {
 });
 
 // @public (undocumented)
-export const moderationLogTypes: readonly ["updateServerSettings", "suspend", "unsuspend", "updateUserNote", "addCustomEmoji", "updateCustomEmoji", "deleteCustomEmoji", "assignRole", "unassignRole", "createRole", "updateRole", "deleteRole", "clearQueue", "promoteQueue", "deleteDriveFile", "deleteNote", "createGlobalAnnouncement", "createUserAnnouncement", "updateGlobalAnnouncement", "updateUserAnnouncement", "deleteGlobalAnnouncement", "deleteUserAnnouncement", "resetPassword", "suspendRemoteInstance", "unsuspendRemoteInstance", "markSensitiveDriveFile", "unmarkSensitiveDriveFile", "resolveAbuseReport", "createInvitation", "createAd", "updateAd", "deleteAd", "createAvatarDecoration", "updateAvatarDecoration", "deleteAvatarDecoration", "unsetUserAvatar", "unsetUserBanner"];
+export const moderationLogTypes: readonly ["updateServerSettings", "suspend", "unsuspend", "updateUserNote", "addCustomEmoji", "updateCustomEmoji", "deleteCustomEmoji", "assignRole", "unassignRole", "createRole", "updateRole", "deleteRole", "clearQueue", "promoteQueue", "deleteDriveFile", "deleteNote", "createGlobalAnnouncement", "createUserAnnouncement", "updateGlobalAnnouncement", "updateUserAnnouncement", "deleteGlobalAnnouncement", "deleteUserAnnouncement", "resetPassword", "suspendRemoteInstance", "unsuspendRemoteInstance", "updateRemoteInstanceNote", "markSensitiveDriveFile", "unmarkSensitiveDriveFile", "resolveAbuseReport", "createInvitation", "createAd", "updateAd", "deleteAd", "createAvatarDecoration", "updateAvatarDecoration", "deleteAvatarDecoration", "unsetUserAvatar", "unsetUserBanner"];
 
 // @public (undocumented)
 type MuteCreateRequest = operations['mute/create']['requestBody']['content']['application/json'];
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index d0d8573b40..9bf79fde71 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -4480,6 +4480,7 @@ export type components = {
       infoUpdatedAt: string | null;
       /** Format: date-time */
       latestRequestReceivedAt: string | null;
+      moderationNote?: string | null;
     };
     GalleryPost: {
       /**
@@ -7213,7 +7214,8 @@ export type operations = {
       content: {
         'application/json': {
           host: string;
-          isSuspended: boolean;
+          isSuspended?: boolean;
+          moderationNote?: string;
         };
       };
     };
diff --git a/packages/misskey-js/src/consts.ts b/packages/misskey-js/src/consts.ts
index 0e446c1215..b690621e98 100644
--- a/packages/misskey-js/src/consts.ts
+++ b/packages/misskey-js/src/consts.ts
@@ -121,6 +121,7 @@ export const moderationLogTypes = [
 	'resetPassword',
 	'suspendRemoteInstance',
 	'unsuspendRemoteInstance',
+	'updateRemoteInstanceNote',
 	'markSensitiveDriveFile',
 	'unmarkSensitiveDriveFile',
 	'resolveAbuseReport',
@@ -261,6 +262,12 @@ export type ModerationLogPayloads = {
 		id: string;
 		host: string;
 	};
+	updateRemoteInstanceNote: {
+		id: string;
+		host: string;
+		before: string | null;
+		after: string | null;
+	};
 	markSensitiveDriveFile: {
 		fileId: string;
 		fileUserId: string | null;
diff --git a/packages/misskey-js/src/entities.ts b/packages/misskey-js/src/entities.ts
index 772d2bbfa1..35503d6d6f 100644
--- a/packages/misskey-js/src/entities.ts
+++ b/packages/misskey-js/src/entities.ts
@@ -95,6 +95,9 @@ export type ModerationLog = {
 } | {
 	type: 'unsuspendRemoteInstance';
 	info: ModerationLogPayloads['unsuspendRemoteInstance'];
+} | {
+	type: 'updateRemoteInstanceNote';
+	info: ModerationLogPayloads['updateRemoteInstanceNote'];
 } | {
 	type: 'markSensitiveDriveFile';
 	info: ModerationLogPayloads['markSensitiveDriveFile'];