A wiring substrate includes first through holes extending through an insulation layer, first via wirings formed in the first through holes, a conductive pattern connected to the first via wirings, recesses formed in the first via wirings, and a protective insulation layer covering the conductive pattern and the first via wirings. The first via wirings, the conductive pattern, the recesses, and the protective insulation layer form an identification mark identifiable as a particular shape including a character or a symbol. Each recess is defined by an upper surface of the corresponding first via wiring and includes a curved side wall and a bottom wall that is located at a lower position than an upper surface of the conductive pattern. The protective insulation layer is thicker over the first via wirings than over the conductive pattern.