A method for working a semiconductor wafer by which a highly accurate flat surface of a semiconductor wafer is formed with a high controllability by working a film formed on the uneven surface of a semiconductor wafer with a vertical working face having a diameter which is 1-2 times larger than that of the wafer while a working solution is supplied from a supplying port provided in the working face. Since the working face has a small diameter, the surface to be worked can be dressed in a high quality. Moreover, since the working face is vertical, any semiconductor wafer can be worked easily, even though the diameter of the wafer is larger.
