An apparatus for removing an unwanted substance from a semiconductor wafer, according to this invention, applies a peeling tape T to a protective tape P on the surface of the semiconductor wafer W. An edge member 28 is placed in contact with the surface of the peeling tape T and run along the protective tape P. The peeling tape T is peeled as being folded back by a large angle of 90 degrees or more at the tip of edge member 28. The protective tape P is peeled and removed along with the peeling tape T from the surface of the wafer. As a result, the unwanted substance is removed with high precision without breaking the wafer W.