On a channel region enclosed by a pair of diffusion layers 13A, 13B, a first insulating layer 15, a charge accumulative layer 17, and a second insulating layer 19 are stacked up in this order, and on the second insulating layer 19, two control gate layers 21A, 21B spaced across a gap G1 are disposed in the middle of the channel width direction. The charge accumulative layer 17 has discrete charge traps, and, accordingly, movement of charge in the layer is limited. In the charge accumulative layer 17, the charges injected depend on the writing voltage applied in control gate layers 21A, 21B and can be localized beneath the control gate layers 21A, 21B through which a writing voltage is applied. The presence or absence of charges can be controlled in every charge accumulative region beneath the control gate layers 21A, 21B, so that multi-value storage in the memory cell can be realized.