According to one embodiment, a semiconductor device includes a wiring board that has a first surface and a second surface opposed to the first surface, a semiconductor chip provided on the first surface, external connection terminals provided on the second surface, a sealing resin layer provided on the first surface, and a conductive shield layer that covers at least a portion of a side surface of the wiring board and the sealing resin layer. The wiring board includes a first ground wire that is electrically connected to the conductive shield layer, and a second ground wire that is electrically connected to the conductive shield layer and is electrically insulated from the first ground wire.