To provide the setting structure and the setting method of a ball joint and the ball joint that can raise the resistance performance against coming off the ball joint by improving the setting strength of the ball joint.

The ball joint 1 is provided with a shank-like base 2 having a ball 20 and a plurality of setting protrusions 3 (31 to 36) that is protruded along the diametric direction of the base 2 and juxtaposed along the center of a central shank P1 on the outer wall of the base 2. The setting protrusions 3 of the ball joint 1 are fitted on the inner wall 65 of the setting hole 60 of the object 6 to be set by drive fitting the base 2 of the ball joint 1 into the setting hole 60 of the object 6 to be set.