CONSTANT VELOCITY UNIVERSAL JOINT

PROBLEM TO BE SOLVED: To reduce an amount of lubricant sealed inside a joint without deteriorating a boot.SOLUTION: The constant velocity universal joint includes a joint outer ring 110 having an opening part 113 on one end, and a joint inner ring 120 transmitting a torque while allowing angle displacement through a ball 130 with the joint outer ring 110. A large-diameter end part 162 of a cylindrical boot 160 for closing the opening part 113 of the joint outer ring 110 is mounted on an opening end part 111 of the joint outer ring 110, and a small-diameter end part 164 of the boot 160 is mounted on a shaft 150 extending from the joint inner ring 120. The lubricant is sealed in an internal space of the joint outer ring 110 and the boot 160. The boot 160 includes a bellows part 166 in which a mountain part 166a and a valley part 166b are alternately and continuously formed, and of which a diameter is reduced from the large-diameter end part 162 to the small-diameter end part 164. The mountain part 166a and the valley part 166b of the bellows part 166 are spirally formed, and an inner surface of the bellows part 166 of the boot 160 is oil-repellent.