A semiconductor device including a transistor on a main surface side of a semiconductor substrate; and a resistance change element on a back-surface side of the semiconductor substrate, wherein the transistor includes a low-resistance section in the semiconductor substrate, the low-resistance section extending to the back surface of the semiconductor substrate, an insulating film is provided in contact with a back surface of the low-resistance section, the insulating film has an opening facing the low-resistance section, and the resistance change element is connected to the low-resistance section through the opening.