diff --git a/mmcv/ops/modulated_deform_conv.py b/mmcv/ops/modulated_deform_conv.py
index <HASH>..<HASH> 100644
--- a/mmcv/ops/modulated_deform_conv.py
+++ b/mmcv/ops/modulated_deform_conv.py
@@ -66,6 +66,7 @@ class ModulatedDeformConv2dFunction(Function):
         # whatever the pytorch version is.
         input = input.type_as(offset)
         weight = weight.type_as(input)
+        bias = bias.type_as(input)
         ctx.save_for_backward(input, offset, mask, weight, bias)
         output = input.new_empty(
             ModulatedDeformConv2dFunction._output_size(ctx, input, weight))
Update modulated_deform_conv.py (#<I>)

change bias to the same type as input