A wiring board includes: a core layer having a through hole therethrough and comprising a first surface and a second surface opposite to the first surface; a first wiring layer formed on the first surface of the core layer and having a first opening which is communicated with the through hole, wherein an opening area of the first opening is larger than that of the through hole in a plan view; an electronic component disposed in the through hole and the first opening and having a first surface, and a second surface opposite to the first surface, the electronic component further having a pair of terminal on the first surface thereof; and a first resin layer filled in the through hole, the first opening and a gap between the pair of terminals so as to cover the second surface and the side surface of the electronic component.