diff --git a/gokart_pipeliner/instantiation_task.py b/gokart_pipeliner/instantiation_task.py
index 11fb2f9..f773196 100644
--- a/gokart_pipeliner/instantiation_task.py
+++ b/gokart_pipeliner/instantiation_task.py
@@ -67,5 +67,14 @@ def requires(self):
         def requires(cls):
             return {t: getattr(cls, t) for t in task_parameters}
 
+        def _get_input_targets(cls, target):
+            """For task name may not be specified."""
+            if target is None:
+                return cls.input()[list(cls.input().keys())[0]]
+            if isinstance(target, str):
+                return cls.input()[target]
+            return target
+
         task.requires = requires
+        task._get_input_targets = _get_input_targets
         return task
diff --git a/test/unittest/test_instatiation_task.py b/test/unittest/test_instatiation_task.py
index 888741c..cd7be50 100644
--- a/test/unittest/test_instatiation_task.py
+++ b/test/unittest/test_instatiation_task.py
@@ -90,3 +90,14 @@ def test_override_requires(self):
         task = InstantiationTask.override_requires(task, ['target'])
         output = task.requires(task)
         self.assertDictEqual(output, {'target': task.target})
+
+    def test_override_requires_get_input_targets(self):
+        task = MockGokartTargetTask
+        task.input = lambda: {'target': 'foo'}
+        task = InstantiationTask.override_requires(task, ['target'])
+
+        output = task._get_input_targets(task, 'target')
+        self.assertEqual(output, 'foo')
+
+        output = task._get_input_targets(task, None)
+        self.assertEqual(output, 'foo')