Problem To provide a process for producing a permanent magnet for use in an automotive IPM motor, which excels in all of corrosion resistance, abrasion resistance, and impact resistance. A protective wall apparatus is positioned around the wafer area, and includes at least one wall contour artifact. The switch circuit connects the n regular registers to the corresponding output lines in a normal state, connects normal registers of upper and lower stages of the broken register by skipping and disabling the broken register if any, and connects normal regular registers and the same number of redundant registers as the broken registers to the n output lines.