A semiconductor device includes: at least one semiconductor element having electrode terminals; a metal plate supporting the semiconductor element; and a wiring board covering the semiconductor element and including a plurality of insulating layers and wiring layers alternately stacked and external connection terminals on a surface, the wiring layers being electrically connected to each other by vias. The electrode terminals and the external connection terminals are electrically connected via at least one of the wiring layers and the vias. At least one of the electrode terminals, the is wiring layers, and the vias is electrically connected to the metal plate.