A phase change memory includes an insulating layer on a substrate, an electrode layer having one pole and an electrode layer having another pole within the insulating layer, an opening portion whose lower portion on an upper portion of the insulating layer is substantially square or substantially rectangular, a phase change portion formed substantially parallel to a surface of the substrate along the respective sides of the lower portion of the opening portion, and two connection electrodes having a pole and connected to the phase change portion at two opposing corners of the lower portion of the opening portion connecting a diode portion connected to the electrode layer having one pole and the phase change portion, and two connection electrodes having another pole and connected to the phase change portion at the other two opposing corners connecting the phase change portion and the electrode layer having another pole.