A package substrate processing method for processing a package substrate in which a plurality of semiconductor chips on a wiring substrate are collectively sealed with a sealing agent is provided. In the package substrate processing method, a protective tape is adhered to the wiring substrate side of the package substrate, the package substrate is divided into a plurality of semiconductor packages, and a shield layer is formed on an upper surface and side surfaces of each package. In this instance, the package substrate is divided in a state in which adhesiveness of an adhesive layer of the protective tape in the periphery of the package substrate is reduced or eliminated, whereby adhesion of a metallic powder scattering at the time of the dividing to the adhesive layer of the protective tape is restrained.