A hot electron (BBHE) is generated close to a drain by tunneling between bands, and bit data writing is performed by injecting the hot electron into a charge storage layer. When Vg is a gate voltage, Vsub is a cell well voltage, Vs is a source voltage and Vd is a drain voltage, a relation of Vg>Vsub>Vs>Vd is satisfied, Vg-Vd is a value of a potential difference required for generating a tunnel current between the bands or higher, and Vsub-Vd is substantially equivalent to a barrier potential of the tunnel insulating film or higher.