According to an embodiment, a semiconductor package includes a semiconductor chip mounted on an interposer board, a encapsulant sealing the semiconductor chip, and a conductive shielding layer covering the encapsulant and at least part of a side surface of the interposer board. The interposer board has plural vias through an insulating substrate. A part of the plural vias has a cutting plane exposing to the side surface of the interposer board and cut in a thickness direction of the interposer board. The cutting plane of the via is electrically connected to the conductive shielding layer.