diff --git a/poetry.lock b/poetry.lock
index dc596d0..a093539 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1925,6 +1925,23 @@ tomli = ">=1.0.0"
 [package.extras]
 testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "pygments (>=2.7.2)", "requests", "xmlschema"]
 
+[[package]]
+name = "pytest-mock"
+version = "3.14.0"
+description = "Thin-wrapper around the mock package for easier use with pytest"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "pytest-mock-3.14.0.tar.gz", hash = "sha256:2719255a1efeceadbc056d6bf3df3d1c5015530fb40cf347c0f9afac88410bd0"},
+    {file = "pytest_mock-3.14.0-py3-none-any.whl", hash = "sha256:0b72c38033392a5f4621342fe11e9219ac11ec9d375f8e2a0c164539e0d70f6f"},
+]
+
+[package.dependencies]
+pytest = ">=6.2.5"
+
+[package.extras]
+dev = ["pre-commit", "pytest-asyncio", "tox"]
+
 [[package]]
 name = "python-dateutil"
 version = "2.8.2"
@@ -3322,4 +3339,4 @@ multidict = ">=4.0"
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.1,<4.0"
-content-hash = "a6c6e6c7efd4b4c0e39ce9d29327b7fc51fa4d621f7a4154ce2a6dae9f089dcf"
+content-hash = "0a438df085b5f588ae2e896ccf7ae833860690af20528afac6bddc963abf564c"
diff --git a/pyproject.toml b/pyproject.toml
index ba0dfab..49e05b4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,6 +28,7 @@ pydantic = "^2.6.3"
 eval-type-backport = "^0.1.3"
 smart-open = "^7.0.1"
 openai = "^1.16.2"
+pytest-mock = "^3.14.0"
 
 [tool.poetry.group.dev.dependencies]
 black = "^23.11.0"
diff --git a/tests/embedders/test_openai.py b/tests/embedders/test_openai.py
index f33eb4d..70b1d96 100644
--- a/tests/embedders/test_openai.py
+++ b/tests/embedders/test_openai.py
@@ -1,13 +1,45 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+
 import numpy as np
+import pytest
+from pytest_mock import MockerFixture
 
-from jmteb.embedders.openai_embedder import OpenAIEmbedder
+from jmteb.embedders import OpenAIEmbedder, TextEmbedder
 
 OUTPUT_DIM = 1536
 
 
-class TestSentenceBertEmbedder:
-    def setup_class(cls):
-        cls.model = OpenAIEmbedder(model="text-embedding-3-small")
+@pytest.fixture(scope="function")
+def mock_openai_embedder(mocker: MockerFixture):
+    mocker.patch("jmteb.embedders.openai_embedder.OpenAI")
+    return OpenAIEmbedder(model="text-embedding-3-small")
+
+
+@dataclass
+class MockData:
+    data: list
+
+
+@dataclass
+class MockEmbedding:
+    embedding: list
+
+
+class MockEmbedder:
+    def create(input: str | list[str], model: str, dimensions: int):
+        if isinstance(input, str):
+            input = [input]
+        return MockData([MockEmbedding(embedding=[0.1] * dimensions)] * len(input))
+
+
+@pytest.mark.usefixtures("mock_openai_embedder")
+class TestOpenAIEmbedder:
+    @pytest.fixture(autouse=True)
+    def setup_class(cls, mocker: MockerFixture, mock_openai_embedder: TextEmbedder):
+        cls.model = mock_openai_embedder
+        cls.mock_create = mocker.patch.object(cls.model.client, "embeddings", new=MockEmbedder)
 
     def test_encode(self):
         embeddings = self.model.encode("任意のテキスト")