A method of manufacturing a wiring substrate, includes forming a laminated body in which a nickel copper alloy layer is formed via an insulating resin layer, on a first wiring layer, forming a via hole reaching the first wiring layer in the nickel copper alloy layer and the insulating resin layer, applying a desmear process to an inside of the via hole, forming a seed layer on the nickel copper alloy layer and an inner surface of the via hole, forming a plating resist in which an opening portion is provided on a part containing the via hole, forming a metal plating layer in the opening portion in the plating resist by an electroplating, removing the plating resist, and forming a second wiring layer by etching the seed layer and the nickel copper alloy layer while using the metal plating layer as a mask.