A brake disk mounting surface is ground by bringing it into contact with an annular grinding wheel, while an inner ring having the brake disk mounting surface is rotated around its center axis, in a state where a part of the annular grinding wheel overlaps with a recess over an entire region of the annular grinding wheel in a radial direction, and in a state where a grinding surface of the annular grinding wheel is inclined with respect to the brake disk mounting surface so that a distance between the brake disk mounting surface and the annular grinding wheel grows larger in a direction toward an outer edge of the brake disk mounting surface.