. . . "FIGS. 2 and 3 are a side view and a plan view showing the structure of the first machining part 20A. As shown in FIGS. 2 and 3, the first machining part 20A comprises a wafer feeding unit 42, a periphery machining unit 44, a notch machining unit 46, and a wafer centering unit 48 in FIG. 1." .