diff --git a/kws/bin/train.py b/kws/bin/train.py
index 3497322..a6c9472 100644
--- a/kws/bin/train.py
+++ b/kws/bin/train.py
@@ -197,7 +197,7 @@ def main():
 
     optimizer = optim.Adam(model.parameters(),
                            lr=configs['optim_conf']['lr'],
-                           weight_decay=configs['optim_conf']['weight_decay'])
+                           weight_decay=configs['optim_conf'].get('weight_decay', 0))
     scheduler = optim.lr_scheduler.ReduceLROnPlateau(
         optimizer,
         mode='min',