A wiring substrate is provided in which a common core member is used and the cost can be reduced. Diameters of the penetrating filled vias (18) are the same and not more than 300 µm, and the penetrating filled vias (18) are formed on a core substrate (20) into a matrix-shape at regular intervals of not more than 2 mm. On the surface of the core substrate (20), a plane wiring pattern (17) is formed through an insulating layer (16). Each pad portion on the wiring pattern (17) is electrically connected with each corresponding via of the filled vias (18) by one to one through a connecting via (28) which penetrates the insulating layer (16), and some of the filled vias (18) are not connected with the wiring pattern (17).