An outer edge of a protective tape projected from a semiconductor wafer is fixed and held by a tape holding section. In the condition, a part of the projected protective tape is caught and supported with a tape supporting section with a face having lower adhesive property provided in the outside of the traveling groove for the cutter. Furthermore, the part of the protective tape having the outer edge fixed and held with the tape holding section is compulsorily deformed and inserted into a depression provided between the tape holding section and the tape supporting section. Thereby, the part of the protective tape located in a traveling groove for the cutter is tensioned outward. A cutter blade is stuck into this tensioned part, and cuts the protective tape all over the peripheries of the wafer