Assembly of a constant velocity universal joint with a boot, comprising: a large-diameter-side mounting portion, which is to be mounted on an outer peripheral surface of an outer joint member of the constant velocity universal joint, and is to be fixed to the outer peripheral surface of the outer joint member through fastening with use of a boot clamp; a small-diameter-side mounting portion, which is to be mounted on an outer peripheral surface of a shaft, and is to be fixed to the outer peripheral surface of the shaft through fastening with use of a boot clamp; a bellows portion configured to integrally couple the large-diameter-side mounting portion and the small-diameter-side mounting portion to each other; and a cylindrical shoulder portion, which is formed at a bellows portion-side end of the large-diameter-side mounting portion, and is connected to the bellows portion through two auxiliary crest portions and one auxiliary trough portion between the two auxiliary crest portions, one of the two auxiliary crest portions on the bellows portion-side being directly connected to the bellows portion, wherein a radial distance between the thickness center of each of the auxiliary crest portions and the thickness center of the auxiliary trough portion is set shorter than a radial distance between the thickness center of a crest portion and the thickness center of a trough portion of the bellows portion excluding the crest portion and the trough portion of the bellows portion closest to the small-diameter-side mounting portion, and wherein a diameter passing through a center (Ho) of the radial distance between each of the auxiliary crest portions and the auxiliary trough portion is set larger than a diameter of the cylindrical shoulder portion, characterized in that the boot has such a deformation mode that, when the constant velocity universal joint forms a high operating angle, the auxiliary crest portions overlap each other in a radial direction of the boot on the outer peripheral surface of the outer joint member, so that it can handle a super high operating angle equal to or larger than 50 degrees. a large-diameter-side mounting portion, which is to be mounted on an outer peripheral surface of an outer joint member of the constant velocity universal joint, and is to be fixed to the outer peripheral surface of the outer joint member through fastening with use of a boot clamp; a small-diameter-side mounting portion, which is to be mounted on an outer peripheral surface of a shaft, and is to be fixed to the outer peripheral surface of the shaft through fastening with use of a boot clamp; a bellows portion configured to integrally couple the large-diameter-side mounting portion and the small-diameter-side mounting portion to each other; and a cylindrical shoulder portion, which is formed at a bellows portion-side end of the large-diameter-side mounting portion, and is connected to the bellows portion through two auxiliary crest portions and one auxiliary trough portion between the two auxiliary crest portions, one of the two auxiliary crest portions on the bellows portion-side being directly connected to the bellows portion, wherein a radial distance between the thickness center of each of the auxiliary crest portions and the thickness center of the auxiliary trough portion is set shorter than a radial distance between the thickness center of a crest portion and the thickness center of a trough portion of the bellows portion excluding the crest portion and the trough portion of the bellows portion closest to the small-diameter-side mounting portion, and wherein a diameter passing through a center (Ho) of the radial distance between each of the auxiliary crest portions and the auxiliary trough portion is set larger than a diameter of the cylindrical shoulder portion,