A wafer processing method for reducing the thickness of a wafer to a predetermined thickness, the wafer having a chamfered portion along the outer circumference thereof. The wafer processing method includes a stacked wafer forming step of attaching a support substrate to the front side of the wafer to thereby form a stacked wafer, and a chamfered portion removing step of positioning a cutting blade having a rotation axis parallel to the stacking direction of the stacked wafer formed by the stacked wafer forming step so that the outer circumference of the cutting blade faces the chamfered portion of the wafer, and then making the cutting blade cut into the wafer from the outer circumference toward the center thereof to thereby partially remove the chamfered portion in the range corresponding to the predetermined thickness from the front side of the wafer.