A wiring substrate includes plural insulating layers including an outermost insulating layer; and plural wiring layers which are alternately laminated between the insulating layers and include outermost wiring layers exposed from the outermost insulating layer and through wirings having electrode pads on end portions of the through wirings and penetrating through the outermost insulating layer, wherein the electrode pads of the through wirings are exposed from the outermost insulating layer, and a part of the outermost wiring layers overlaps the end portions of the through wirings and is connected to the through wirings.