A wiring board including a core substrate made of an insulative material and having a penetrating portion, a first interlayer insulation layer formed on the surface of the core substrate, a first conductive circuit formed on the surface of the first interlayer insulation layer, a first via conductor formed in the first interlayer insulation layer, and an electronic component accommodated in the penetrating portion of the core substrate and including a semiconductor element, a bump body mounted on the semiconductor element, a conductive circuit connected to the bump body, an interlayer resin insulation layer formed on the conductive circuit, and a via conductor formed in the interlayer resin insulation layer. The first via conductor has a tapering direction which is opposite of a tapering direction of the via conductor in the electronic component.