To easily join pipes together in a short time even if a sufficient spatial allowance does not exist by arranging mutually connecting locking parts in both end parts of an end having ring shaped main body part having an almost U-shaped groove part on an inner peripheral surface.

In an end having ring 1 shaped main body part 1 locking parts 2 and 2 to be hookingly locked are formed in respective end parts. For example, a claw-shaped or a hook-shaped locking recessed part 3 is integrally formed in a locking part 2 on one end 1a, and a claw-shaped or hook-shaped locking projection part 4 is integrally formed in the locking part 2 on the other end 1b, respectively. A cross-sectional almost U-shaped groove part 5 is formed on an inner peripheral surface of the main body part 1. On the other hand, a cover member 6 composed of a leaf spring is fixed to an outer peripheral surface of the main body part 1. This clamp is used to connect plural pipes to each other, and butts flange parts of first and second pipes having a flange part on one end against each other, and these flange parts are inserted into a clamp grove part 5, and when the locking parts 2 and 2 are locked on each other, since it can be assembled by simple operation, workability can be improved.