An adhesive tape is supplied to a back face side of a ring frame, joined to the ring frame with a joining roller, and cut by pivoting a cutter blade along the ring frame. Subsequently, an inspection ring of an inspecting mechanism perform suction on the adhesive tape while contacting the adhesive tape adjacent an inner periphery of the ring frame. Separation of the adhesive tape from the ring frame is determined based on variations of the suction pressure. When the separation of the adhesive tape from the ring frame is detected, the adhesive tape is joined again with the joining roller provided in the cutter mechanism.