A wiring board includes a core substrate having an opening portion and a through hole adjacent to the opening portion, a capacitor positioned in the opening portion, and a through-hole conductor formed in the through hole of the core substrate and having a conductor filling the through hole. The core substrate has a first surface and a second surface on the opposite side of the first surface, the opening portion of the core substrate penetrates from the first surface to the second surface, the through-hole conductor has a first conductive portion and a second conductive portion connected to the first conductive portion in the core substrate, the first conductive portion of the through-hole conductor becomes narrower from the first surface toward the second surface, and the second conductive portion of the through-hole conductor becomes narrower from the second surface toward the first surface.