To lock and fix a pipe with a collet stably by forming a collet inserted into a pipe joint main body, and provided with a head part which is brought into pressurizing contact with the taper inner surface of the pipe joint main body, a cylindrical wall whose diameter is contracted freely, and an edge bitten into the outer surface of a connected pipe, and arranging a female type locking recessed/projection on the inlet inner surface of the pipe joint main body.

In the case where pipings are connected to each other, a connected pipe p is inserted into a collet 2, the collet 2 is pulled, the head part 22 of the collet 2 is brought into pressurizing contact with the taper inner surface 12 of a pipe joint main body 1, the diameter of a cylindrical wall 21 is contracted, an edge 23 is bitten into the outer surface of the connected pipe p, and also the male type locking recessed/projection (b) is locked with the female locking recessed/projection (a) of the pipe joint main body 1. After connecting work is completed, pipe shaft direction component force is acted in a direction made the collet 2 apart from the pipe joint main body 1 when pulling of the collet 2 is released, a lock condition is held stably since the pipe shaft direction component force is supported at the lock position (ab) of the inlet inner surface of the pipe joint main body 1 and the collet 2.