Resin CVJ boot with distinct large and small crest portions

In a resin CVJ boot containing a shaft and comprising a bellows portion consisting of four or more continuous crest and root portions, a large-diameter mounting portion provided at one end of the bellows portion and a small-diameter mounting portion provided at the other end of the bellows portion, the resin CVJ boot characterized in that the CVJ boot has a large crest group and a small crest group and means for distinguishing said large crest group closer to the large-diameter mounting portion from a bending point obtained when the bellows portion displays an S-shaped bend having an expanded side and a compressed side from said small crest group directly connected to the large crest group and being closer to the small-diameter mounting portion, and for preventing slant faces forming the root portion which is closest to the S-shaped bend, from coming into contact with each other on said compressed side and, in the event that the slant faces do come into contact with each other on said compressed side, causing the slant faces to contact each other over a broad contact area, the large crest group being directly connected to the small crest group at the root portion closest to the S-shaped bend, the crest groups being shaped so that no root portion comes into contact with the shaft when the bellows portion displays the S-shaped bend.