diff --git a/moco/builder.py b/moco/builder.py
index 7952a981c..9d1d4dd29 100644
--- a/moco/builder.py
+++ b/moco/builder.py
@@ -60,7 +60,7 @@ def _momentum_update_key_encoder(self):
         for param_q, param_k in zip(
             self.encoder_q.parameters(), self.encoder_k.parameters()
         ):
-            param_k.data = param_k.data * self.m + param_q.data * (1.0 - self.m)
+            param_k.mul_(self.m).add_(param_q.mul(1. - self.m))
 
     @torch.no_grad()
     def _dequeue_and_enqueue(self, keys):