diff --git a/packages/frontend/src/account.ts b/packages/frontend/src/account.ts
index c3f3337c9d..a202a9aae9 100644
--- a/packages/frontend/src/account.ts
+++ b/packages/frontend/src/account.ts
@@ -108,8 +108,8 @@ function fetchAccount(token: string, id?: string, forceShowDialog?: boolean): Pr
 		})
 			.then(res => new Promise<Account | { error: Record<string, any> }>((done2, fail2) => {
 				if (res.status >= 500 && res.status < 600) {
-				// サーバーエラー(5xx)の場合をrejectとする
-				// （認証エラーなど4xxはresolve）
+					// サーバーエラー(5xx)の場合をrejectとする
+					// （認証エラーなど4xxはresolve）
 					return fail2(res);
 				}
 				res.json().then(done2, fail2);
diff --git a/packages/frontend/src/boot/main-boot.ts b/packages/frontend/src/boot/main-boot.ts
index 7459ea0fa5..944881aba5 100644
--- a/packages/frontend/src/boot/main-boot.ts
+++ b/packages/frontend/src/boot/main-boot.ts
@@ -83,6 +83,14 @@ export async function mainBoot() {
 			}
 		});
 
+		for (const announcement of $i.announcements.filter(x => x.display === 'dialog')) {
+			popup(defineAsyncComponent(() => import('@/components/MkAnnouncementDialog.vue')), {
+				announcement,
+			}, {}, 'closed');
+		}
+
+		// TODO: announcementCreatedイベント監視
+
 		if ($i.isDeleted) {
 			alert({
 				type: 'warning',
diff --git a/packages/frontend/src/components/MkAnnouncementDialog.vue b/packages/frontend/src/components/MkAnnouncementDialog.vue
new file mode 100644
index 0000000000..5c4a6adffb
--- /dev/null
+++ b/packages/frontend/src/components/MkAnnouncementDialog.vue
@@ -0,0 +1,58 @@
+<!--
+SPDX-FileCopyrightText: syuilo and other misskey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<MkModal ref="modal" :zPriority="'middle'" @closed="$emit('closed')">
+	<div :class="$style.root">
+		<div :class="$style.title">{{ announcement.title }}</div>
+		<div :class="$style.text">{{ announcement.text }}</div>
+		<MkButton primary full @click="ok">{{ i18n.ts.ok }}</MkButton>
+	</div>
+</MkModal>
+</template>
+
+<script lang="ts" setup>
+import { onMounted, shallowRef } from 'vue';
+import * as misskey from 'misskey-js';
+import MkModal from '@/components/MkModal.vue';
+import MkButton from '@/components/MkButton.vue';
+import { i18n } from '@/i18n';
+
+const props = withDefaults(defineProps<{
+	announcement: misskey.entities.Announcement;
+}>(), {
+});
+
+const modal = shallowRef<InstanceType<typeof MkModal>>();
+
+function ok() {
+	modal.value.close();
+}
+
+onMounted(() => {
+});
+</script>
+
+<style lang="scss" module>
+.root {
+	margin: auto;
+	position: relative;
+	padding: 32px;
+	min-width: 320px;
+	max-width: 480px;
+	box-sizing: border-box;
+	text-align: center;
+	background: var(--panel);
+	border-radius: var(--radius);
+}
+
+.title {
+	font-weight: bold;
+}
+
+.text {
+	margin: 1em 0;
+}
+</style>
diff --git a/packages/misskey-js/src/entities.ts b/packages/misskey-js/src/entities.ts
index b9771d1964..b4e98f8c64 100644
--- a/packages/misskey-js/src/entities.ts
+++ b/packages/misskey-js/src/entities.ts
@@ -104,6 +104,7 @@ export type MeDetailed = UserDetailed & {
 	noCrawle: boolean;
 	receiveAnnouncementEmail: boolean;
 	usePasswordLessLogin: boolean;
+	announcements: Announcement[];
 	[other: string]: any;
 };
 
@@ -413,6 +414,9 @@ export type Announcement = {
 	text: string;
 	title: string;
 	imageUrl: string | null;
+	display: 'normal' | 'banner' | 'dialog';
+	needConfirmationToRead: boolean;
+	forYou: boolean;
 	isRead?: boolean;
 };