A method comprising: a step of preforming a plurality of bulging portions on a substantially circular plate blank, the bulging portions being located concentrically and circumferentially outward of a bolt hole, each of the bulging portions being a base of a reinforcing portion of a spoke; a step of forming a plurality of prototypical decorative holes on the respective bulging portions to form a prototypically-shaped spoke between the adjacent prototypical decorative holes; a step of forming a disk flange by bending an outer circumferential portion of the plate blank, on which the prototypical decorative holes are formed, at a right angle to be substantially parallel to a wheel axial direction, so that an outer periphery of a resultant decorative hole forms an upper end edge of the disk flange; and a step of forming the spoke by providing the prototypically-shaped spoke with the reinforcing portion.