diff --git a/train_network.py b/train_network.py
index 0fd8cc0f..9956a905 100644
--- a/train_network.py
+++ b/train_network.py
@@ -213,7 +213,13 @@ def train(args):
     # 学習に必要なクラスを準備する
     print("prepare optimizer, data loader etc.")
 
-    trainable_params = network.prepare_optimizer_params(args.text_encoder_lr, args.unet_lr, args.learning_rate)
+    # 後方互換性を確保するよ
+    try:
+        trainable_params = network.prepare_optimizer_params(args.text_encoder_lr, args.unet_lr, args.learning_rate)
+    except TypeError:
+        print("Deprecated: use prepare_optimizer_params(text_encoder_lr, unet_lr, learning_rate) instead of prepare_optimizer_params(text_encoder_lr, unet_lr)")
+        trainable_params = network.prepare_optimizer_params(args.text_encoder_lr, args.unet_lr)
+
     optimizer_name, optimizer_args, optimizer = train_util.get_optimizer(args, trainable_params)
 
     # dataloaderを準備する