A wiring substrate includes a core layer having a hole penetrating therethrough in a thickness direction thereof, and having a projecting part projecting from an inner wall of the hole toward an inner space of the hole, the projecting part being situated at a border that divides a plurality of areas in the hole, a plurality of electronic components disposed in the areas, respectively, the electronic components being arranged at a spaced interval with the projecting part therebetween, and a resin layer filling the hole and supporting the electronic components, wherein a thickness of the projecting part in the thickness direction of the core layer decreases toward a tip of the projecting part.