When forming a toothed portion on the outer section of a blank by contacting a tooth profile-forming portion of a forming die with a curved portion of the blank, the first projection of the blank is accommodated in a first depression, and a load is applied axially to a center section of the blank so a material of the blank flows radially outward. The material of the blank at the first projection flows in the axial direction to inside the first depression, and the material of the blank at an intermediate section between the center and the outer section flows in axially to inside a second depression to form a second projection. When the load is maximized, a space is provided between a toothed portion and the tooth profile-forming portion, between the first projection and the forming die, and between the second projection and the forming die.