The demand for reducing the size and increasing the degree of integration of semiconductor memory devices has increased. In a semiconductor memory device, a smoothing capacitor which has to be provided therein for stabilizing a power supply voltage etc. is formed in an underlying layer of memory cells A and B to overlap the two memory cells A and B which are adjacent each other. Thus, an area occupied by the smoothing capacitor having a large capacity can be reduced to increase the degree of integration, and the smoothing capacitor having a large capacity can be provided in the semiconductor memory device.