A wiring substrate includes an insulation substrate including a first surface, a second surface on an opposite side of the first surface, and first and second through-holes penetrating the insulation substrate from the first surface to the second surface; a wiring layer formed on the first surface of the insulation substrate; a first via formed in the first through-hole and connected to the wiring layer; a bus line positioned away from the wiring layer and the first via, and formed on the first surface of the insulation substrate; and a second via formed in the second through-hole and connected to the bus line.