diff --git a/src/config.ts b/src/config.ts
index 86bd26d..0174350 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -14,6 +14,7 @@ type Config = {
 	mecabDic?: string;
 	memoryDir?: string;
 	earthQuakeMonitorPort?: number;
+	openAiApiKey?: string;
 };
 
 const config = require('../config.json');
diff --git a/src/constants/ENDPOINTS.ts b/src/constants/ENDPOINTS.ts
new file mode 100644
index 0000000..85ef559
--- /dev/null
+++ b/src/constants/ENDPOINTS.ts
@@ -0,0 +1,5 @@
+const ENDPOINTS = {
+	OPEN_AI: 'https://api.openai.com/v1',
+} as const;
+
+export default ENDPOINTS;
diff --git a/src/constants/GPT3_MODELS.ts b/src/constants/GPT3_MODELS.ts
new file mode 100644
index 0000000..3a4f274
--- /dev/null
+++ b/src/constants/GPT3_MODELS.ts
@@ -0,0 +1,11 @@
+/**
+ * @see https://beta.openai.com/docs/models/overview
+ */
+const GPT3_MODELS = {
+	davinci: 'text-davinci-003',
+	curie: 'text-curie-001',
+	babbage: 'text-babbage-001',
+	ada: 'text-ada-001',
+};
+
+export default GPT3_MODELS;
diff --git a/src/index.ts b/src/index.ts
index 96ef87e..e2bf4fa 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -39,6 +39,7 @@ import Earthquake from './modules/earthquake';
 import DicModule from './modules/dic';
 import MenuModule from './modules/menu';
 import GetColorModule from './modules/color';
+import ChatGPT from './modules/chatGPT';
 
 console.log('   __    ____  _____  ___ ');
 console.log('  /__\\  (_  _)(  _  )/ __)');
@@ -72,6 +73,7 @@ promiseRetry((retry) => {
 	new 藍(account, [
 		new CoreModule(),
 		new ReminderModule(),
+		new ChatGPT(),
 		new SummonCat(),
 		new EmojiModule(),
 		new EmojiReactModule(),
diff --git a/src/modules/chatGPT/index.ts b/src/modules/chatGPT/index.ts
new file mode 100644
index 0000000..058ef2c
--- /dev/null
+++ b/src/modules/chatGPT/index.ts
@@ -0,0 +1,29 @@
+import autobind from 'autobind-decorator';
+import Module from '@/module';
+import Message from '@/message';
+import fetchChatGPT from '@/utils/fetchChatGPT';
+
+class ChatGPT extends Module {
+	public readonly name = 'ChatGPT';
+
+	@autobind
+	public install() {
+		return {
+			mentionHook: this.mentionHook,
+		};
+	}
+
+	@autobind
+	private async mentionHook(msg: Message) {
+		if (msg.text && (msg.text.includes('ChatGPT'))) {
+			// msg.textから"ChatGPT "を削除
+			const prompt = msg.text.replace('ChatGPT ', '');
+			msg.reply(await fetchChatGPT({prompt}));
+			return true;
+		} else {
+			return false;
+		}
+	}
+}
+
+export default ChatGPT;
diff --git a/src/utils/fetchChatGPT.ts b/src/utils/fetchChatGPT.ts
new file mode 100644
index 0000000..b15cf05
--- /dev/null
+++ b/src/utils/fetchChatGPT.ts
@@ -0,0 +1,42 @@
+import {isNil} from 'lodash';
+import ENDPOINTS from '@/constants/ENDPOINTS.js';
+import GPT3_MODELS from '@/constants/GPT3_MODELS.js';
+import config from '@/config';
+
+const COMPLETION_ENDPOINT = `${ENDPOINTS.OPEN_AI}/completions`;
+
+// 0~1
+const TEMPERATURE = 0.9;
+// 2048 or 4000
+const MAX_TOKENS = 4000;
+
+/**
+ * @see https://beta.openai.com/docs/api-reference/completions/create
+ */
+async function fetchChatGPT({prompt}: {prompt: string}): Promise<string> {
+	if (isNil(config.openAiApiKey)) {
+		return '利用する準備ができていないようです...?';
+	}
+	const options = {
+		model: GPT3_MODELS.davinci,
+		max_tokens: MAX_TOKENS,
+		temperature: TEMPERATURE,
+		prompt,
+	};
+
+	const response = await fetch(COMPLETION_ENDPOINT, {
+		method: 'POST',
+		headers: {
+			'Content-Type': 'application/json',
+			'Authorization': `Bearer ${config.openAiApiKey}`,
+		},
+		body: JSON.stringify(options),
+	});
+
+	const results = await response.json();
+	// results.choicesの中からランダムに返す
+	const randomIndex = Math.floor(Math.random() * results.choices.length);
+	return results.choices[randomIndex].text;
+}
+
+export default fetchChatGPT;