According to one embodiment, a manufacturing method of a semiconductor device is disclosed. The method includes: (a) forming cutting grooves in an element formation surface of a semiconductor wafer on which semiconductor elements are formed; (b) applying a protection tape on the element formation surface of the semiconductor wafer; (c) grinding a rear surface of the semiconductor wafer to thin the semiconductor wafer and to divide the semiconductor wafer into a plurality of semiconductor chips on which the semiconductor elements are formed; (d) forming an adhesive layer on the rear surface of the semiconductor wafer; (e) separating and cutting the adhesive layer for each of the semiconductor chips; and (f) removing the protection tape. The (e) is performed by spraying a high-pressure air to the adhesive layer formed on the rear surface of the semiconductor wafer while melting or softening the adhesive layer by heating.