diff --git a/jquantsapi/client_v2.py b/jquantsapi/client_v2.py
index 5cf9348..9db484a 100644
--- a/jquantsapi/client_v2.py
+++ b/jquantsapi/client_v2.py
@@ -9,6 +9,7 @@
 import pandas as pd  # type: ignore
 import requests
 from requests.adapters import HTTPAdapter
+from requests.exceptions import HTTPError
 from urllib3.util import Retry
 
 if sys.version_info >= (3, 11):
@@ -216,6 +217,21 @@ def _base_headers(self) -> dict[str, str]:
             f"p/{platform.python_version()}",
         }
 
+    def _raise_for_status(self, resp: requests.Response) -> None:
+        """
+        raise_for_status の拡張版。
+        エラー時にレスポンスボディのメッセージを含めた HTTPError を送出する。
+        """
+        if resp.ok:
+            return
+        try:
+            body = resp.json()
+            detail = body.get("message", resp.text)
+        except Exception:
+            detail = resp.text
+        msg = f"{resp.status_code} for url: {resp.url} body: {detail}"
+        raise HTTPError(msg, response=resp)
+
     def _get(
         self, url: str, params: Optional[dict[str, Any]] = None
     ) -> requests.Response:
@@ -225,7 +241,7 @@ def _get(
         session = self._request_session()
         headers = self._base_headers()
         resp = session.get(url, params=params, headers=headers, timeout=30)
-        resp.raise_for_status()
+        self._raise_for_status(resp)
         return resp
 
     def _get_paginated(
@@ -1334,7 +1350,7 @@ def download_bulk(self, key: str, output_path: str) -> None:
         # ファイルをダウンロード
         session = self._request_session()
         response = session.get(url, stream=True, timeout=300)
-        response.raise_for_status()
+        self._raise_for_status(response)
 
         # ファイルに書き込み
         with open(output_path, "wb") as f:
diff --git a/tests/test_client_v2.py b/tests/test_client_v2.py
index a35df53..cfb09ac 100644
--- a/tests/test_client_v2.py
+++ b/tests/test_client_v2.py
@@ -4,6 +4,7 @@
 
 import pandas as pd
 import pytest
+import requests
 from dateutil import tz
 
 import jquantsapi
@@ -401,3 +402,93 @@ def test_get_bulk():
         args, _ = mock_get.call_args
         assert args[1] == {"key": "2024/01/01/eq_master.csv"}
         assert ret == "https://example.com/data.csv"
+
+
+def test_get_raises_with_api_error_message():
+    """_get()がエラー時にAPIのメッセージを含むHTTPErrorを送出することを確認"""
+    mock_resp = MagicMock()
+    mock_resp.ok = False
+    mock_resp.status_code = 403
+    mock_resp.url = "https://api.jquants.com/v2/equities/master"
+    mock_resp.json.return_value = {"message": "Forbidden - Invalid API key"}
+    mock_resp.text = '{"message": "Forbidden - Invalid API key"}'
+
+    with patch.object(
+        jquantsapi.ClientV2, "_load_config", return_value={"api_key": "dummy_key"}
+    ), patch.object(
+        jquantsapi.ClientV2, "_request_session"
+    ) as mock_session, patch.object(
+        jquantsapi.ClientV2, "_base_headers", return_value={}
+    ):
+        mock_session.return_value.get.return_value = mock_resp
+        cli = jquantsapi.ClientV2()
+        with pytest.raises(
+            requests.exceptions.HTTPError, match="Forbidden - Invalid API key"
+        ):
+            cli._get("https://api.jquants.com/v2/equities/master")
+
+
+def test_get_raises_with_text_body_on_json_error():
+    """レスポンスがJSONでない場合にテキストボディでHTTPErrorを送出することを確認"""
+    mock_resp = MagicMock()
+    mock_resp.ok = False
+    mock_resp.status_code = 500
+    mock_resp.url = "https://api.jquants.com/v2/equities/master"
+    mock_resp.json.side_effect = ValueError("No JSON")
+    mock_resp.text = "Internal Server Error"
+
+    with patch.object(
+        jquantsapi.ClientV2, "_load_config", return_value={"api_key": "dummy_key"}
+    ), patch.object(
+        jquantsapi.ClientV2, "_request_session"
+    ) as mock_session, patch.object(
+        jquantsapi.ClientV2, "_base_headers", return_value={}
+    ):
+        mock_session.return_value.get.return_value = mock_resp
+        cli = jquantsapi.ClientV2()
+        with pytest.raises(
+            requests.exceptions.HTTPError, match="Internal Server Error"
+        ):
+            cli._get("https://api.jquants.com/v2/equities/master")
+
+
+def test_get_success_does_not_raise():
+    """正常レスポンスの場合はエラーが送出されないことを確認"""
+    mock_resp = MagicMock()
+    mock_resp.ok = True
+    mock_resp.status_code = 200
+
+    with patch.object(
+        jquantsapi.ClientV2, "_load_config", return_value={"api_key": "dummy_key"}
+    ), patch.object(
+        jquantsapi.ClientV2, "_request_session"
+    ) as mock_session, patch.object(
+        jquantsapi.ClientV2, "_base_headers", return_value={}
+    ):
+        mock_session.return_value.get.return_value = mock_resp
+        cli = jquantsapi.ClientV2()
+        result = cli._get("https://api.jquants.com/v2/equities/master")
+        assert result == mock_resp
+
+
+def test_get_error_has_response_attribute():
+    """HTTPErrorにresponseオブジェクトが付与されることを確認（後方互換性）"""
+    mock_resp = MagicMock()
+    mock_resp.ok = False
+    mock_resp.status_code = 401
+    mock_resp.url = "https://api.jquants.com/v2/equities/master"
+    mock_resp.json.return_value = {"message": "Unauthorized"}
+    mock_resp.text = '{"message": "Unauthorized"}'
+
+    with patch.object(
+        jquantsapi.ClientV2, "_load_config", return_value={"api_key": "dummy_key"}
+    ), patch.object(
+        jquantsapi.ClientV2, "_request_session"
+    ) as mock_session, patch.object(
+        jquantsapi.ClientV2, "_base_headers", return_value={}
+    ):
+        mock_session.return_value.get.return_value = mock_resp
+        cli = jquantsapi.ClientV2()
+        with pytest.raises(requests.exceptions.HTTPError) as exc_info:
+            cli._get("https://api.jquants.com/v2/equities/master")
+        assert exc_info.value.response == mock_resp