diff --git a/README.md b/README.md
index 22ae88f..60b5748 100644
--- a/README.md
+++ b/README.md
@@ -54,16 +54,14 @@ poetry run whisper_streaming --language en --model tiny --host 0.0.0.0 --port 80
 ```
 
 You can set ``--allow-padding`` and other options.
-(``-n`` for hosts makes no sense)
 
 ### Client
 
 ```bash
-poetry run python -m whisper_streaming.websocket_client --host ADDRESS_OF_HOST --port 8000 -n 20
+poetry run whisper_streaming --model tiny --host ADDRESS_OF_HOST --port 8000 --mode client
 ```
 
 You can set ``-n`` and other options.
-(``--allow-padding`` for clients makes no sense)
 
 ## Tips
 
diff --git a/whisper_streaming/cli.py b/whisper_streaming/cli.py
index e4ad406..5af0db2 100644
--- a/whisper_streaming/cli.py
+++ b/whisper_streaming/cli.py
@@ -15,6 +15,7 @@ from whisper.tokenizer import LANGUAGES, TO_LANGUAGE_CODE
 from whisper_streaming.schema import WhisperConfig
 from whisper_streaming.serve import serve_with_websocket
 from whisper_streaming.transcriber import WhisperStreamingTranscriber
+from whisper_streaming.websocket_client import run_websocket_client
 
 logger = getLogger(__name__)
 
@@ -58,13 +59,11 @@ def get_opts() -> argparse.Namespace:
         default=None,
         choices=sorted(LANGUAGES.keys())
         + sorted([k.title() for k in TO_LANGUAGE_CODE.keys()]),
-        required=True,
     )
     parser.add_argument(
         "--model",
         type=str,
         choices=available_models(),
-        required=True,
     )
     parser.add_argument(
         "--device",
@@ -113,10 +112,29 @@ def get_opts() -> argparse.Namespace:
         "--allow-padding",
         action="store_true",
     )
+    parser.add_argument(
+        "--mode",
+        choices=["client"],
+    )
 
     return parser.parse_args()
 
 
+def get_wshiper(*, opts):
+    config = WhisperConfig(
+        model_name=opts.model,
+        language=opts.language,
+        device=opts.device,
+        beam_size=opts.beam_size,
+        temperatures=opts.temperature,
+        allow_padding=opts.allow_padding,
+    )
+
+    logger.debug(f"WhisperConfig: {config}")
+    wsp = WhisperStreamingTranscriber(config=config)
+    return wsp
+
+
 def main() -> None:
     opts = get_opts()
     basicConfig(
@@ -135,26 +153,30 @@ def main() -> None:
     except Exception:
         pass
 
-    config = WhisperConfig(
-        model_name=opts.model,
-        language=opts.language,
-        device=opts.device,
-        beam_size=opts.beam_size,
-        temperatures=opts.temperature,
-        allow_padding=opts.allow_padding,
-    )
-
-    logger.debug(f"WhisperConfig: {config}")
-    wsp = WhisperStreamingTranscriber(config=config)
     if opts.host is not None and opts.port is not None:
-        asyncio.run(
-            serve_with_websocket(
-                wsp=wsp,
-                host=opts.host,
-                port=opts.port,
+        if opts.mode == "client":
+            assert opts.language is None
+            assert opts.model is None
+            asyncio.run(
+                run_websocket_client(
+                    opts=opts,
+                )
+            )
+        else:
+            assert opts.language is not None
+            assert opts.model is not None
+            wsp = get_wshiper(opts=opts)
+            asyncio.run(
+                serve_with_websocket(
+                    wsp=wsp,
+                    host=opts.host,
+                    port=opts.port,
+                )
             )
-        )
     else:
+        assert opts.language is not None
+        assert opts.model is not None
+        wsp = get_wshiper(opts=opts)
         transcribe_from_mic(
             wsp=wsp,
             sd_device=opts.mic,
diff --git a/whisper_streaming/websocket_client.py b/whisper_streaming/websocket_client.py
index 4857c61..2eac7f8 100644
--- a/whisper_streaming/websocket_client.py
+++ b/whisper_streaming/websocket_client.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
-import argparse
 import asyncio
-from logging import DEBUG, INFO, basicConfig, getLogger
+from logging import getLogger
 from typing import Optional, Union
 
 import sounddevice as sd
@@ -68,44 +67,7 @@ async def transcribe_from_mic_and_send(
                 idx += 1
 
 
-def get_opts() -> argparse.Namespace:
-    parser = argparse.ArgumentParser()
-    parser.add_argument(
-        "--host",
-        required=True,
-        help="host of websocker server",
-    )
-    parser.add_argument(
-        "--port",
-        type=int,
-        required=True,
-        help="Port number of websocker server",
-    )
-
-    parser.add_argument(
-        "--mic",
-    )
-    parser.add_argument(
-        "--num_block",
-        "-n",
-        type=int,
-        default=160,
-        help="Number of operation unit",
-    )
-    parser.add_argument(
-        "--debug",
-        action="store_true",
-    )
-
-    return parser.parse_args()
-
-
-async def main() -> None:
-    opts = get_opts()
-    basicConfig(
-        level=DEBUG if opts.debug else INFO,
-        format="[%(asctime)s] %(module)s.%(funcName)s:%(lineno)d %(levelname)s -> %(message)s",
-    )
+async def run_websocket_client(*, opts) -> None:
     global q
     global loop
     loop = asyncio.get_running_loop()
@@ -117,7 +79,3 @@ async def main() -> None:
         host=opts.host,
         port=opts.port,
     )
-
-
-if __name__ == "__main__":
-    asyncio.run(main())