diff --git a/src/misc/convert-host.ts b/src/misc/convert-host.ts
new file mode 100644
index 0000000000..d4478bd85b
--- /dev/null
+++ b/src/misc/convert-host.ts
@@ -0,0 +1,21 @@
+import config from '../config';
+import { toUnicode, toASCII } from 'punycode';
+
+export function getFullApAccount(username: string, host: string) {
+	return host ? `${username}@${toApHost(host)}` : `${username}@${toApHost(config.host)}`;
+}
+
+export function isSelfHost(host: string) {
+	if (host == null) return true;
+	return toApHost(config.host) === toApHost(host);
+}
+
+export function toDbHost(host: string) {
+	if (host == null) return null;
+	return toUnicode(host.toLowerCase());
+}
+
+export function toApHost(host: string) {
+	if (host == null) return null;
+	return toASCII(host.toLowerCase());
+}
diff --git a/src/queue/processors/db/export-blocking.ts b/src/queue/processors/db/export-blocking.ts
index e56aec94ac..7f32c06472 100644
--- a/src/queue/processors/db/export-blocking.ts
+++ b/src/queue/processors/db/export-blocking.ts
@@ -8,7 +8,7 @@ import addFile from '../../../services/drive/add-file';
 import User from '../../../models/user';
 import dateFormat = require('dateformat');
 import Blocking from '../../../models/blocking';
-import config from '../../../config';
+import { getFullApAccount } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('export-blocking');
 
@@ -56,7 +56,7 @@ export async function exportBlocking(job: Bull.Job, done: any): Promise<void> {
 
 		for (const block of blockings) {
 			const u = await User.findOne({ _id: block.blockeeId }, { fields: { username: true, host: true } });
-			const content = u.host ? `${u.username}@${u.host}` : `${u.username}@${config.host}`;
+			const content = getFullApAccount(u.username, u.host);
 			await new Promise((res, rej) => {
 				stream.write(content + '\n', err => {
 					if (err) {
diff --git a/src/queue/processors/db/export-following.ts b/src/queue/processors/db/export-following.ts
index 1d8a501b78..019414072a 100644
--- a/src/queue/processors/db/export-following.ts
+++ b/src/queue/processors/db/export-following.ts
@@ -8,7 +8,7 @@ import addFile from '../../../services/drive/add-file';
 import User from '../../../models/user';
 import dateFormat = require('dateformat');
 import Following from '../../../models/following';
-import config from '../../../config';
+import { getFullApAccount } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('export-following');
 
@@ -56,7 +56,7 @@ export async function exportFollowing(job: Bull.Job, done: any): Promise<void> {
 
 		for (const following of followings) {
 			const u = await User.findOne({ _id: following.followeeId }, { fields: { username: true, host: true } });
-			const content = u.host ? `${u.username}@${u.host}` : `${u.username}@${config.host}`;
+			const content = getFullApAccount(u.username, u.host);
 			await new Promise((res, rej) => {
 				stream.write(content + '\n', err => {
 					if (err) {
diff --git a/src/queue/processors/db/export-mute.ts b/src/queue/processors/db/export-mute.ts
index 6f2dd6df13..5ded7cf651 100644
--- a/src/queue/processors/db/export-mute.ts
+++ b/src/queue/processors/db/export-mute.ts
@@ -8,7 +8,7 @@ import addFile from '../../../services/drive/add-file';
 import User from '../../../models/user';
 import dateFormat = require('dateformat');
 import Mute from '../../../models/mute';
-import config from '../../../config';
+import { getFullApAccount } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('export-mute');
 
@@ -56,7 +56,7 @@ export async function exportMute(job: Bull.Job, done: any): Promise<void> {
 
 		for (const mute of mutes) {
 			const u = await User.findOne({ _id: mute.muteeId }, { fields: { username: true, host: true } });
-			const content = u.host ? `${u.username}@${u.host}` : `${u.username}@${config.host}`;
+			const content = getFullApAccount(u.username, u.host);
 			await new Promise((res, rej) => {
 				stream.write(content + '\n', err => {
 					if (err) {
diff --git a/src/queue/processors/db/export-user-lists.ts b/src/queue/processors/db/export-user-lists.ts
index 6b5f72c15e..dfbf152ec0 100644
--- a/src/queue/processors/db/export-user-lists.ts
+++ b/src/queue/processors/db/export-user-lists.ts
@@ -7,8 +7,8 @@ import { queueLogger } from '../../logger';
 import addFile from '../../../services/drive/add-file';
 import User from '../../../models/user';
 import dateFormat = require('dateformat');
-import config from '../../../config';
 import UserList from '../../../models/user-list';
+import { getFullApAccount } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('export-user-lists');
 
@@ -46,7 +46,7 @@ export async function exportUserLists(job: Bull.Job, done: any): Promise<void> {
 		});
 
 		for (const u of users) {
-			const acct = u.host ? `${u.username}@${u.host}` : `${u.username}@${config.host}`;
+			const acct = getFullApAccount(u.username, u.host);
 			const content = `${list.title},${acct}`;
 			await new Promise((res, rej) => {
 				stream.write(content + '\n', err => {
diff --git a/src/queue/processors/db/import-following.ts b/src/queue/processors/db/import-following.ts
index 9b8b9f9614..ad9129c1f5 100644
--- a/src/queue/processors/db/import-following.ts
+++ b/src/queue/processors/db/import-following.ts
@@ -3,13 +3,13 @@ import * as mongo from 'mongodb';
 
 import { queueLogger } from '../../logger';
 import User from '../../../models/user';
-import config from '../../../config';
 import follow from '../../../services/following/create';
 import DriveFile from '../../../models/drive-file';
 import { getOriginalUrl } from '../../../misc/get-drive-file-url';
 import parseAcct from '../../../misc/acct/parse';
 import resolveUser from '../../../remote/resolve-user';
 import { downloadTextFile } from '../../../misc/download-text-file';
+import { isSelfHost, toDbHost } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('import-following');
 
@@ -31,11 +31,11 @@ export async function importFollowing(job: Bull.Job, done: any): Promise<void> {
 	for (const line of csv.trim().split('\n')) {
 		const { username, host } = parseAcct(line.trim());
 
-		let target = host === config.host ? await User.findOne({
+		let target = isSelfHost(host) ? await User.findOne({
 			host: null,
 			usernameLower: username.toLowerCase()
 		}) : await User.findOne({
-			host: host,
+			host: toDbHost(host),
 			usernameLower: username.toLowerCase()
 		});
 
diff --git a/src/queue/processors/db/import-user-lists.ts b/src/queue/processors/db/import-user-lists.ts
index 7250920090..50d3c649d4 100644
--- a/src/queue/processors/db/import-user-lists.ts
+++ b/src/queue/processors/db/import-user-lists.ts
@@ -3,7 +3,6 @@ import * as mongo from 'mongodb';
 
 import { queueLogger } from '../../logger';
 import User from '../../../models/user';
-import config from '../../../config';
 import UserList from '../../../models/user-list';
 import DriveFile from '../../../models/drive-file';
 import { getOriginalUrl } from '../../../misc/get-drive-file-url';
@@ -11,6 +10,7 @@ import parseAcct from '../../../misc/acct/parse';
 import resolveUser from '../../../remote/resolve-user';
 import { pushUserToUserList } from '../../../services/user-list/push';
 import { downloadTextFile } from '../../../misc/download-text-file';
+import { isSelfHost, toDbHost } from '../../../misc/convert-host';
 
 const logger = queueLogger.createSubLogger('import-user-lists');
 
@@ -47,11 +47,11 @@ export async function importUserLists(job: Bull.Job, done: any): Promise<void> {
 			});
 		}
 
-		let target = host === config.host ? await User.findOne({
+		let target = isSelfHost(host) ? await User.findOne({
 			host: null,
 			usernameLower: username.toLowerCase()
 		}) : await User.findOne({
-			host: host,
+			host: toDbHost(host),
 			usernameLower: username.toLowerCase()
 		});