diff --git a/chainerrl/experiments/train_agent.py b/chainerrl/experiments/train_agent.py
index cd8b028a0..26acd04f7 100644
--- a/chainerrl/experiments/train_agent.py
+++ b/chainerrl/experiments/train_agent.py
@@ -107,6 +107,8 @@ def train_agent_with_evaluation(
         max_episode_len (int): Maximum episode length.
         step_offset (int): Time step from which training starts.
         eval_explorer: Explorer used for evaluation.
+        eval_max_episode_len (int or None): Maximum episode length of
+            evaluation runs. If set to None, max_episode_len is used instead.
         eval_env: Environment used for evaluation.
         successful_score (float): Finish training if the mean score is greater
             or equal to this value if not None