diff --git a/ch06/train_rnnlm.py b/ch06/train_rnnlm.py
index 16255926..eacbf795 100644
--- a/ch06/train_rnnlm.py
+++ b/ch06/train_rnnlm.py
@@ -30,7 +30,8 @@
 trainer = RnnlmTrainer(model, optimizer)
 
 # 勾配クリッピングを適用して学習
-trainer.fit(xs, ts, max_epoch, batch_size, time_size, max_grad)
+trainer.fit(xs, ts, max_epoch, batch_size, time_size, max_grad,
+            eval_interval=20)
 trainer.plot(ylim=(0, 500))
 
 # テストデータで評価