PURPOSE: To increase the capacity of a capacitor without causing an increase in an element area and lowering of dielectric strength.

CONSTITUTION: An N-type epitaxial layer 102 is laminated on a P-type semiconductor substrate 100 and further an N+ diffused layer 104 is formed thereon. A dielectric layer 106 of a silicon oxide is formed and a conductive layer 108 of polysilicon is laminated on a region wherein a capacitor is to be formed. Next, a dielectric layer 110 of polysilicon is formed, and after a phosphorus glass PSG layer 112 is applied for coating, a conductive layer 114 of aluminum is laminated and connected to an electrode A. The conductive layer 114 of aluminum and the N+ diffused layer 104 are connected through a contact hole and they are connected to an electrode B. A capacitor 1 of the dielectric layer 106 and a capacitor C2 of the dielectric layer 110 are connected in parallel and the capacity is C1+C2.