A wiring substrate includes a core, a first wiring layer formed on a first surface of the core, a second wiring layer formed on a second surface of the core, and an electronic component partially accommodated in the cavity and including a projected portion projected from the first opening of the core. A first insulating layer covers a side surface of the electronic component and the first surface of the core and fills a portion of the cavity. A second insulating layer covers the first insulating layer. A third insulating layer covers the second surface of the core. The remainder of the cavity that is not filled with the first insulating layer is filled with the third insulating layer.