The disclosure concerns a memory including a floating body provided in a semiconductor layer between a source and a drain and storing data; a first gate dielectric provided on a first surface of the body; a first gate electrode provided on the first surface via the first gate dielectric; a second gate dielectric provided on a second surface of the body different from the first surface; a second gate electrode provided on the second surface via the second gate dielectric; a driver driving the first gate electrode and the second gate electrode; and a sense amplifier writing into the memory cells first data showing a sate of a small charge amount in a state that a voltage of the second gate electrode at a data writing time is brought closer to a potential of the source layer than a voltage of the second gate electrode at a data holding time.