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, a plurality of electronic components disposed in the hole and arranged side by side at a spaced interval in a plan view, the electronic components having side portions thereof, the side portions being engaged with the projecting part, and a resin layer filling the hole and supporting the electronic components.