To prevent a reverse turn caused by an expanded deformation of a bent portion of a boot for a universal joint while preventing the incursion of water or the like into the inside of the universal joint.

The boot 60 for a universal joint made of a flexible material has a large-diameter mounting portion 61 mounted at one shaft 11 side, a small-diameter mounting portion 62 mounted at the other shaft 12 side, and the bent portion 63 with an approximately U-shaped section in the middle of the large-diameter mounting portion 61 and the small-diameter mounting portion 62. Numerous follow portions 64 are arranged on the inside of the bent portion 63.