A method of processing a laminated wafer in which a first wafer is laminated on a second wafer, the method including: a laminated wafer forming step of forming the laminated wafer by laminating the first wafer on the second wafer; a modified layer forming step of forming a modified layer within the first wafer by positioning a focusing point of a laser beam within the first wafer and moving the first wafer in a horizontal direction relative to the focusing point while applying the laser beam, the modified layer forming step being performed before or after the laminated wafer forming step is performed; and a separating step of separating part of the first wafer from the laminated wafer with the modified layer as a boundary, the separating step being performed after the laminated wafer forming step and the modified layer forming step are performed.