A method for manufacturing a wiring substrate includes forming a conductor layer including first and second pads, forming a resin insulating layer on the conductor layer, forming, in the insulating layer, a first opening exposing the first pad and a second opening exposing the second pad, forming a covering layer on the insulating layer such that the covering layer covers the first and second openings, forming a third opening in the covering layer such that the third opening communicates with the first opening and the first pad is exposed in the third opening, forming, on a surface of the first pad, a protective film formed of material different from material forming the conductor layer, removing the covering layer from the insulating layer, and forming a conductor post on the second pad such that the conductor post is formed of material that is same as the material forming the conductor layer.