To provide a method capable of simply and certainly attaching a larger diameter bead of boots into a larger diameter bead groove of the end outer periphery of a ball housing without scattering grease outside.

The method of attaching the boots to the ball joint for attaching the larger diameter bead 11 into the larger diameter bead groove 6 of the end outer periphery of the ball housing 1 in the ball joint J is used when the boots having a large diameter bead 11 on one end and a small diameter bead 12 having a diameter smaller than the diameter of the large diameter bead on the other end is mounted on the ball joint J. The method includes the first process of reversing the boots B inside out and the second process of fitting the larger diameter bead 11 into the larger diameter bead groove 6 while reversing the reversed boots B' reversed in the first process inside out to restore the original shape again.