Abstract: A memory cell is formed by flip-flop connection of a load transistor pair of a first load transistor and a second load transistor and a drive transistor pair of a first drive transistor and a second drive transistor. A first switch which is controlled by a wordline and a second switch which is activated only at the time of the write operation are connected in series to a first memory node. The second switch is serially coupled between the first memory node and the first drive transistor. An electric current is injected from a sense amplifier into a bitline pair selected at the time of the read operation, to detect an impedance which varies with the signal potential at the first memory node.