In a manufacturing method of a semiconductor device of an embodiment, a plurality of semiconductor packages, as objects to be processed, each including a semiconductor chip mounted on a wiring board and a sealing resin layer, and a tray including a plurality of housing parts are prepared. The semiconductor packages are respectively disposed in the plurality of housing parts of the tray. A metal material is sputtered on the semiconductor packages disposed in the housing parts, to thereby form a conductive shield layer covering an upper surface and side surfaces of each of the sealing resin layers and at least a part of side surfaces of each of the wiring boards.