A ball joint is provided that when a load equal to or greater than a first predetermined value is applied in the axial direction of a ball stud, if a cushion seat is deformed by a predetermined amount, an opposing surface portion contacts a first load receiving portion of a ball seat, preventing the cushion seat from being deformed by a predetermined amount in the central axis direction. When a load equal to or greater than a second predetermined value greater than the first is applied in the axial direction of the ball stud, a second load receiving portion of the ball seatcontacts a bottom surface portion of an inner chamber of a socket, whereby an axial load onto the cushion seat is reduced, and the ball seat prevents the cushion seat from being deformed by a predetermined amount or more in the axial direction.