A resistive random access memory including, an insulating layer, a hard mask layer, a bottom electrode, a memory cell and a top electrode is provided. The insulating layer is disposed on the bottom electrode. The insulating layer has a contact hole having a first width. The hard mask layer has an opening. A portion of the memory cell is exposed from the opening and has a second width smaller than the first width. The top electrode is disposed on the insulating layer and is coupled with the memory cell.