A dynamic RAM integrated circuit of the one-element memory cell type is provided with a plurality of data lines, a sense amplifier, a plurality of word lines disposed in a manner to intersect with the data lines, and memory cells disposed at the points of intersection between the data lines and the word lines. The RAM includes a P-type semiconductor substrate and an N-type well region formed in the substrate. The memory cells are disposed within the well, and the sense amplifier, which is connected to the data lines, is constructed of a pair of N-channel MOSFETs formed in the semiconductor substrate and a pair of P-channel MOSFETs formed in the well region.