To provide a forming method by which weight of a wheel disk can be lightened without spoiling the appearance.

A plate-like base material 1 shown in Fig. 2 (A) is prepared. An intermediate material 4 is obtained by drawing the base material 1 in a preforming stage shown in Fig. 2 (B), (C). The intermediate material 1 has a recessed part 2 the bottom wall 2a of which is inclined toward the middle from the peripheral edge part. In a regular forming stage as shown in Fig. 2 (D), a hub fixing part 11 is obtained by forming the bottom wall 2a of the recessed part 2 of the intermediate material 4 into a disk shape. In this way, the thickness of the radius part 15 enclosing the hub fixing part 11 can be increased.