A back grinding method for a wafer includes covering a face-side surface of the wafer with a resin film, and cutting the surface of the resin film to form a flat surface parallel to the face-side surface of the wafer. The wafer is held with the surface of the resin film in contact with a suction surface of a chuck table in a grinding apparatus, and the exposed back-side surface of the wafer is ground. Unevenness in thickness of the resin film is suppressed, whereby the thickness of the wafer subjected to back grinding is made to be uniform.