diff --git a/dpgen/tools/auto_gen_param.py b/dpgen/tools/auto_gen_param.py
index bd6d0f79b..cf47a85d7 100755
--- a/dpgen/tools/auto_gen_param.py
+++ b/dpgen/tools/auto_gen_param.py
@@ -55,11 +55,11 @@ class Iteration:
 
     @property
     def index_iteration(self):
-        return self._index_iteration  # pylint: disable=no-member
+        return self._index_iteration
 
     @index_iteration.setter
     def index_iteration(self, value):
-        self._index_sub_iteration = value
+        self._index_iteration = value
 
     @classmethod
     def register_iteration(cls):
diff --git a/tests/tools/test_auto_gen_param.py b/tests/tools/test_auto_gen_param.py
new file mode 100644
index 000000000..9c87a40af
--- /dev/null
+++ b/tests/tools/test_auto_gen_param.py
@@ -0,0 +1,17 @@
+import unittest
+
+from dpgen.tools.auto_gen_param import Iteration
+
+
+class TestIterationIndex(unittest.TestCase):
+    def test_index_iteration_round_trip(self):
+        iteration = Iteration([50])
+        registered_index = iteration.index_iteration
+
+        self.assertIsInstance(registered_index, int)
+        iteration.index_iteration = 7
+        self.assertEqual(iteration.index_iteration, 7)
+
+
+if __name__ == "__main__":
+    unittest.main()