A semiconductor device which provides compactness and enhanced drain withstand voltage. The semiconductor device includes: a gate electrode; a source electrode spaced from the gate electrode; a drain electrode located opposite to the source electrode with respect to the gate electrode in a plan view and spaced from the gate electrode; at least one field plate electrode located between the gate and drain electrodes in a plan view, provided over the semiconductor substrate through an insulating film and spaced from the gate electrode, source electrode and drain electrode; and at least one field plate contact provided in the insulating film, coupling the field plate electrode to the semiconductor substrate. The field plate electrode extends from the field plate contact at least either toward the source electrode or toward the drain electrode in a plan view.