diff --git a/torch_geometric/nn/conv/hypergraph_conv.py b/torch_geometric/nn/conv/hypergraph_conv.py
index 411330d3ec21..74db56af3678 100644
--- a/torch_geometric/nn/conv/hypergraph_conv.py
+++ b/torch_geometric/nn/conv/hypergraph_conv.py
@@ -174,9 +174,9 @@ def forward(self, x: Tensor, hyperedge_index: Tensor,
             alpha = (torch.cat([x_i, x_j], dim=-1) * self.att).sum(dim=-1)
             alpha = F.leaky_relu(alpha, self.negative_slope)
             if self.attention_mode == 'node':
-                alpha = softmax(alpha, hyperedge_index[1], num_nodes=x.size(0))
+                alpha = softmax(alpha, hyperedge_index[1], num_nodes=num_edges)
             else:
-                alpha = softmax(alpha, hyperedge_index[0], num_nodes=x.size(0))
+                alpha = softmax(alpha, hyperedge_index[0], num_nodes=num_nodes)
             alpha = F.dropout(alpha, p=self.dropout, training=self.training)
 
         D = scatter(hyperedge_weight[hyperedge_index[1]], hyperedge_index[0],