An aspect of the present invention inheres in a semiconductor device includes a semiconductor region, a source electrode and a drain electrode, which are provided on a main surface of the semiconductor region, a gate electrode exhibiting normally-off characteristics, the gate electrode being provided above the main surface of the semiconductor region while interposing a p-type material film therebetween, and being arranged between the source electrode and the drain electrode, and a fourth electrode that is provided on the main surface of the semiconductor region, and is arranged between the gate electrode and the drain electrode.