diff --git a/networks/lora.py b/networks/lora.py
index 9243f1e1..b936bfb2 100644
--- a/networks/lora.py
+++ b/networks/lora.py
@@ -31,7 +31,7 @@ class LoRAModule(torch.nn.Module):
       self.lora_up = torch.nn.Linear(lora_dim, out_dim, bias=False)
 
     if type(alpha) == torch.Tensor:
-      alpha = alpha.detach().numpy()
+      alpha = alpha.detach().float().numpy()                              # without casting, bf16 causes error
     alpha = lora_dim if alpha is None or alpha == 0 else alpha
     self.scale = alpha / self.lora_dim
     self.register_buffer('alpha', torch.tensor(alpha))                    # 定数として扱える