To prevent damaging of an insertion port projected part by a lock ring at the time of connecting pipes and to simplify pipe connection without recovering jig to prevent marring after construction.

A protective member 4 made of a support ring 2 engaged with a socket opening side part of a lock ring storage groove 11b on an inner surface of a socket 11 and a skirt type cover 3 extended to an inner surface of a lock ring 13 stored in the lock ring storage groove by the support ring 2 is installed from a socket opening side part of the lock ring storage groove 11b over to the inner surface of the lock ring 13 and an insertion port projected part 1a of an insertion port 1 makes contact with the lock ring 13 through the skirt type cover 3 and passes through it at the time of connecting pipes.