diff --git a/src/server/activitypub.ts b/src/server/activitypub.ts
index 3094d69b15..be8a118b9d 100644
--- a/src/server/activitypub.ts
+++ b/src/server/activitypub.ts
@@ -165,7 +165,8 @@ router.get('/users/:user', async (ctx, next) => {
 
 	const user = await Users.findOne({
 		id: userId,
-		host: null
+		host: null,
+		isSuspended: false
 	});
 
 	await userInfo(ctx, user);
@@ -176,7 +177,8 @@ router.get('/@:user', async (ctx, next) => {
 
 	const user = await Users.findOne({
 		usernameLower: ctx.params.user.toLowerCase(),
-		host: null
+		host: null,
+		isSuspended: false
 	});
 
 	await userInfo(ctx, user);
diff --git a/src/server/api/endpoints/admin/suspend-user.ts b/src/server/api/endpoints/admin/suspend-user.ts
index 6ba0d91505..1202315541 100644
--- a/src/server/api/endpoints/admin/suspend-user.ts
+++ b/src/server/api/endpoints/admin/suspend-user.ts
@@ -2,7 +2,7 @@ import $ from 'cafy';
 import { ID } from '../../../../misc/cafy-id';
 import define from '../../define';
 import deleteFollowing from '../../../../services/following/delete';
-import { Users, Followings } from '../../../../models';
+import { Users, Followings, Notifications } from '../../../../models';
 import { User } from '../../../../models/entities/user';
 import { insertModerationLog } from '../../../../services/insert-moderation-log';
 import { doPostSuspend } from '../../../../services/suspend-user';
@@ -55,6 +55,7 @@ export default define(meta, async (ps, me) => {
 	(async () => {
 		await doPostSuspend(user).catch(e => {});
 		await unFollowAll(user).catch(e => {});
+		await readAllNotify(user).catch(e => {});
 	})();
 });
 
@@ -75,3 +76,12 @@ async function unFollowAll(follower: User) {
 		await deleteFollowing(follower, followee, true);
 	}
 }
+
+async function readAllNotify(notifier: User) {
+	await Notifications.update({
+		notifierId: notifier.id,
+		isRead: false,
+	}, {
+		isRead: true
+	});
+}
diff --git a/src/server/api/endpoints/i/notifications.ts b/src/server/api/endpoints/i/notifications.ts
index aa72e9a176..cd00501a2e 100644
--- a/src/server/api/endpoints/i/notifications.ts
+++ b/src/server/api/endpoints/i/notifications.ts
@@ -3,7 +3,7 @@ import { ID } from '../../../../misc/cafy-id';
 import { readNotification } from '../../common/read-notification';
 import define from '../../define';
 import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Notifications, Followings, Mutings } from '../../../../models';
+import { Notifications, Followings, Mutings, Users } from '../../../../models';
 
 export const meta = {
 	desc: {
@@ -72,6 +72,10 @@ export default define(meta, async (ps, user) => {
 		.select('muting.muteeId')
 		.where('muting.muterId = :muterId', { muterId: user.id });
 
+	const suspendedQuery = Users.createQueryBuilder('users')
+		.select('id')
+		.where('users.isSuspended = TRUE');
+
 	const query = makePaginationQuery(Notifications.createQueryBuilder('notification'), ps.sinceId, ps.untilId)
 		.andWhere(`notification.notifieeId = :meId`, { meId: user.id })
 		.leftJoinAndSelect('notification.notifier', 'notifier');
@@ -79,6 +83,8 @@ export default define(meta, async (ps, user) => {
 	query.andWhere(`notification.notifierId NOT IN (${ mutingQuery.getQuery() })`);
 	query.setParameters(mutingQuery.getParameters());
 
+	query.andWhere(`notification.notifierId NOT IN (${ suspendedQuery.getQuery() })`);
+
 	if (ps.following) {
 		query.andWhere(`((notification.notifierId IN (${ followingQuery.getQuery() })) OR (notification.notifierId = :meId))`, { meId: user.id });
 		query.setParameters(followingQuery.getParameters());
diff --git a/src/server/api/endpoints/users/show.ts b/src/server/api/endpoints/users/show.ts
index d17dd51c0a..f49017a8c3 100644
--- a/src/server/api/endpoints/users/show.ts
+++ b/src/server/api/endpoints/users/show.ts
@@ -66,13 +66,18 @@ export const meta = {
 export default define(meta, async (ps, me) => {
 	let user;
 
+	const isAdminOrModerator = me && (me.isAdmin || me.isModerator);
+
 	if (ps.userIds) {
 		if (ps.userIds.length === 0) {
 			return [];
 		}
 
-		const users = await Users.find({
+		const users = await Users.find(isAdminOrModerator ? {
 			id: In(ps.userIds)
+		} : {
+			id: In(ps.userIds),
+			isSuspended: false
 		});
 
 		return await Promise.all(users.map(u => Users.pack(u, me, {
@@ -93,7 +98,7 @@ export default define(meta, async (ps, me) => {
 			user = await Users.findOne(q);
 		}
 
-		if (user == null) {
+		if (user == null || (!isAdminOrModerator && user.isSuspended)) {
 			throw new ApiError(meta.errors.noSuchUser);
 		}
 
diff --git a/src/server/web/index.ts b/src/server/web/index.ts
index dff6e139c8..06c7274f5a 100644
--- a/src/server/web/index.ts
+++ b/src/server/web/index.ts
@@ -101,7 +101,8 @@ const getFeed = async (acct: string) => {
 	const { username, host } = parseAcct(acct);
 	const user = await Users.findOne({
 		usernameLower: username.toLowerCase(),
-		host
+		host,
+		isSuspended: false
 	});
 
 	return user && await packFeed(user);
@@ -149,7 +150,8 @@ router.get(['/@:user', '/@:user/:sub'], async (ctx, next) => {
 	const { username, host } = parseAcct(ctx.params.user);
 	const user = await Users.findOne({
 		usernameLower: username.toLowerCase(),
-		host
+		host,
+		isSuspended: false
 	});
 
 	if (user != null) {
@@ -170,6 +172,7 @@ router.get(['/@:user', '/@:user/:sub'], async (ctx, next) => {
 		ctx.set('Cache-Control', 'public, max-age=30');
 	} else {
 		// リモートユーザーなので
+		// モデレータがAPI経由で参照可能にするために404にはしない
 		await next();
 	}
 });
@@ -177,7 +180,8 @@ router.get(['/@:user', '/@:user/:sub'], async (ctx, next) => {
 router.get('/users/:user', async ctx => {
 	const user = await Users.findOne({
 		id: ctx.params.user,
-		host: null
+		host: null,
+		isSuspended: false
 	});
 
 	if (user == null) {
diff --git a/src/server/well-known.ts b/src/server/well-known.ts
index 94c871eca2..63837a9b70 100644
--- a/src/server/well-known.ts
+++ b/src/server/well-known.ts
@@ -49,7 +49,8 @@ router.get('/.well-known/nodeinfo', async ctx => {
 router.get(webFingerPath, async ctx => {
 	const fromId = (id: User['id']): Record<string, any> => ({
 		id,
-		host: null
+		host: null,
+		isSuspended: false
 	});
 
 	const generateQuery = (resource: string) =>
@@ -63,7 +64,8 @@ router.get(webFingerPath, async ctx => {
 	const fromAcct = (acct: Acct): Record<string, any> | number =>
 		!acct.host || acct.host === config.host.toLowerCase() ? {
 			usernameLower: acct.username,
-			host: null
+			host: null,
+			isSuspended: false
 		} : 422;
 
 	if (typeof ctx.query.resource !== 'string') {