Abstract: In a peripheral circuit of a static RAM composed of memory cells of polysilicon high resistance type, there is provided a word line potential deviating circuit which sets the potential of a selected word line during writing operation to be the potential Vvol, the value of which is higher than that of a supplied potential Vdd. The word line potential deviating circuit includes a ring-oscillator circuit, a deviation timing signal generating circuit, a step-up gate control signal generating circuit, a step-up potential generating circuit, a word line supplied potential mixing circuit, and a word line potential supply control circuit.