. . " the 11th embodiment, where FIG. 20A is a plan view and [0173] FIG. 20B is a sectional view; [0174] FIGS. 21A to 21C are views of an example of the layout of a cathode member and an anode member of the polishing ring wheel according to the 11th embodiment; [0175] FIGS. 22A to 22C are views of another example of the layout of a cathode member and an anode member of the polishing ring wheel accordin" . .