A wiring substrate includes an insulating layer, a conductor layer formed on the insulating layer and including a conductor pad, and a solder resist layer formed on the insulating layer such that the solder resist layer has an opening entirely exposing an upper surface and a side surface of the conductor pad. The conductor layer is formed such that the conductor pad has a pad body extending along a surface of the insulating layer, and a protective layer covering an upper surface and a side surface of the pad body and including material different from material of the pad body, and the pad body of the conductor pad has a notch part formed at a peripheral edge portion of the pad body such that the notch part separates a lower surface of the pad body and the surface of the insulating layer and is filled with the protective layer.