diff --git a/src/tools/ai/extract-user-keywords.ts b/src/tools/ai/extract-user-keywords.ts
new file mode 100644
index 000000000..9f21ae2e1
--- /dev/null
+++ b/src/tools/ai/extract-user-keywords.ts
@@ -0,0 +1,94 @@
+const MeCab = require('mecab-async');
+
+import Post from '../../api/models/post';
+import User from '../../api/models/user';
+import config from '../../conf';
+
+const mecab = new MeCab();
+if (config.categorizer.mecab_command) mecab.command = config.categorizer.mecab_command;
+
+function tokenize(text: string) {
+	const tokens = this.mecab.parseSync(text)
+		// キーワードのみ
+		.filter(token => token[1] == '名詞' && (token[2] == '固有名詞' || token[2] == '一般'))
+		// 取り出し
+		.map(token => token[0]);
+
+	return tokens;
+}
+
+// Fetch all users
+User.find({}, {
+	fields: {
+		_id: true
+	}
+}).then(users => {
+	let i = -1;
+
+	const x = cb => {
+		if (++i == users.length) return cb();
+		extractKeywordsOne(users[i]._id, () => x(cb));
+	};
+
+	x(() => {
+		console.log('complete');
+	});
+});
+
+async function extractKeywordsOne(id, cb) {
+	console.log(`extract keywords of ${id} ...`);
+
+	// Fetch recent posts
+	const recentPosts = await Post.find({
+		user_id: id,
+		text: {
+			$exists: true
+		}
+	}, {
+		sort: {
+			_id: -1
+		},
+		limit: 1000,
+		fields: {
+			_id: false,
+			text: true
+		}
+	});
+
+	// 投稿が少なかったら中断
+	if (recentPosts.length < 10) {
+		return cb();
+	}
+
+	const keywords = {};
+
+	// Extract keywords from recent posts
+	recentPosts.forEach(post => {
+		const keywordsOfPost = tokenize(post.text);
+
+		keywordsOfPost.forEach(keyword => {
+			if (keywords[keyword]) {
+				keywords[keyword]++;
+			} else {
+				keywords[keyword] = 1;
+			}
+		});
+	});
+
+	// Sort keywords by frequency
+	const keywordsSorted = Object.keys(keywords).sort((a, b) => keywords[b] - keywords[a]);
+
+	// Lookup top 10 keywords
+	const topKeywords = keywordsSorted.slice(0, 10);
+
+	process.stdout.write(' >>> ' + topKeywords.join(' '));
+
+	// Save
+	User.update({ _id: id }, {
+		$set: {
+			keywords: topKeywords
+		}
+	}).then(() => {
+		cb();
+	});
+}