A tripod type constant velocity universal joint that includes an outer joint member having three track grooves axially extending on an inner circumferential surface thereof; an inner joint member having three radially projecting trunnions; a boot fitted to an outer periphery of the outer joint member at an end portion and to a shaft extended from the inner joint member at another end portion to seal an inner region of the joint; wherein the outer joint member includes a first reduced-thickness portion on an outer periphery thereof in a region corresponding to the region between the track grooves, and a second reduced-thickness portion on an outer periphery thereof in a region corresponding to the region where the track grooves are located; and wherein the second reduced-thickness portion is of a groove shape axially extending with respect to the outer joint member.