A semiconductor device comprises: a MOS transistor including: a semiconductor substrate; a source region, formed in the semiconductor substrate, that comprises an impurity of a first conductive type; a drain region, formed in the semiconductor substrate, that comprises an impurity of the first conductive type; and a gate electrode, formed through a gate insulating film on the semiconductor substrate, between the source region and the drain region; an impurity region of the first conductive type formed in the semiconductor substrate; an impurity region of a second conductive type to be opposite to the first conductive type formed in the semiconductor substrate; and a wiring provided to connect each of the impurity region of the first conductive type and the impurity region of the second conductive type to the gate electrode.