A wiring board is provided, wherein electrical function of the wiring board is normal, the wiring board has a front side, a reverse side opposite to the front side, an opening and an interconnection layer, the opening penetrates the wiring board and connects the front side and the reverse side, and the interconnection layer is located on the front side and extends toward the opening. A component is bonded to the wiring board, wherein electrical function of the component is normal, the component has an active surface, a back surface opposite to the active surface, and a working area located on the active surface, the active surface is bonded to the interconnection layer, the component is located in the opening, and the active surface and the front side of the wiring board face in a same direction. An encapsulant is filled into the opening, so as to cover the component and expose the working area.