PURPOSE: To further increase a ratio of capacitances between two states of a storage cell in which information is written.

CONSTITUTION: Bandlike diffused wirings 21, 22, 23..., parallel to a silicon substrate 1 are formed and polysilicon wirings 11, 12, 13... are formed in a bandlike state in a direction perpendicular to the wirings 21, 22, 23 through two-layer insulating films 2, 3. In storage cells in which storage cells are formed an intersections of the diffused wirings and the polysilicon wirings to form a storage cell having small capacitance according to information to be written, a polysilicon layer 4 fixed to a GND potential is formed between the films 2 and 3, a polysilicon film 4a is formed in a storage cell having a large capacitance, and the film 4a is connected to the polysilicon wirings via through holes of the film 3 of an upper layer.