A pipe joint provided with a joint main body having a male screw portion and a cap nut screwed on the male screw portion of the joint main body. And, the pipe joint has a C-shaped stop ring having an opening on its periphery. The stop ring, having an inner blade to cut a concave groove on a peripheral face of a pipe, is disposed as a peripheral face contacts a tapered inner face of a hole portion of the cap nut. Further, a corotation means is provided to rotate the cap nut and the stop ring together.