A wiring substrate includes an insulating layer having a through hole, a first conductor layer formed on a first surface of the insulating layer, a second conductor layer formed on a second surface of the insulating layer, an interlayer connection conductor formed in the through hole such that the interlayer connection conductor is connecting the first and second conductor layers, and a resin body formed in the through hole of the insulating layer such that a volume occupancy rate of the resin body is in a range of 30% to 55% in the through hole. The interlayer connection conductor is formed such that the interlayer connection conductor has a length in a range of 1000 μm to 2000 μm in a thickness direction of the insulating layer and that a volume occupancy rate of the interlayer connection conductor is in a range of 45% to 70% in the through hole.