A hat portion of a wheel disk includes a hat inner inclined circumferential portion and a hat outer inclined circumferential portion. At least one of the hat inner inclined circumferential portion and the hat outer inclined circumferential portion includes: a plurality of curved protruding circumferential portions that protrude toward a surface side into a curved shape; and at least one curved recessed circumferential portion that is provided between the adjacent curved protruding circumferential portions and that is recessed toward a back side into a curved shape. The hat portion of this construction provides a significant effect in improving stiffness because of the shapes of the curved protruding circumferential portions and the curved recessed circumferential portion. Consequently, an automobile wheel has improved overall stiffness and strength. Therefore, a car on which the automobile wheel is mounted can provide increased driving stability.