diff --git a/dpgen/simplify/simplify.py b/dpgen/simplify/simplify.py
index 24205fda3..30b3472ac 100644
--- a/dpgen/simplify/simplify.py
+++ b/dpgen/simplify/simplify.py
@@ -221,7 +221,9 @@ def run_model_devi(iter_index, jdata, mdata):
     commands = []
     run_tasks = ["."]
     # get models
-    models = glob.glob(os.path.join(work_path, "graph*pb"))
+    suffix = _get_model_suffix(jdata)
+    models = glob.glob(os.path.join(work_path, f"graph*{suffix}"))
+    assert len(models) > 0, "No model file found."
     model_names = [os.path.basename(ii) for ii in models]
     task_model_list = []
     for ii in model_names:
diff --git a/tests/simplify/test_run_model_devi.py b/tests/simplify/test_run_model_devi.py
index e928afa8e..28d5732e5 100644
--- a/tests/simplify/test_run_model_devi.py
+++ b/tests/simplify/test_run_model_devi.py
@@ -17,6 +17,9 @@ class TestOneH5(unittest.TestCase):
     def setUp(self):
         work_path = Path("iter.000000") / "01.model_devi"
         work_path.mkdir(parents=True, exist_ok=True)
+        # fake models
+        for ii in range(4):
+            (work_path / f"graph.{ii:03d}.pb").touch()
         with tempfile.TemporaryDirectory() as tmpdir:
             with open(Path(tmpdir) / "test.xyz", "w") as f:
                 f.write(