A wiring board includes a core structure including a core substrate, and a buildup structure formed on the core structure and including an interlayer insulating layer and a conductive layer. The interlayer insulating layer does not contain inorganic fiber and includes a resin and an inorganic filler, and the conductive layer is formed on the interlayer insulating layer such that the inorganic filler in the interlayer insulating layer is not in contact with the conductive layer.