diff --git a/onnxslim/core/pattern/fusion/convbn.py b/onnxslim/core/pattern/fusion/convbn.py
index f4aa0e0..56f1e13 100644
--- a/onnxslim/core/pattern/fusion/convbn.py
+++ b/onnxslim/core/pattern/fusion/convbn.py
@@ -29,7 +29,7 @@ def rewrite(self, opset=11):
         conv_transpose_node = self.conv_0
         conv_transpose_node_users = get_node_users(conv_transpose_node)
         node = self.bn_0
-        if len(conv_transpose_node_users) == 1:
+        if len(conv_transpose_node_users) == 1 and all([isinstance(value, gs.Constant) for value in node.inputs[1:]]):
             conv_transpose_weight = conv_transpose_node.inputs[1].values
             bn_node = node
             bn_scale = bn_node.inputs[1].values