To provide a joint capable of moving without ring runners being not caught in a curtain rail constituted by movably inserting an inner pipe into an outer pipe and fitting and holding a joint into an inner pipe inserting side of the outer pipe.

The joint 5 has an inner pipe supporting part 12 laterally movably inserting and supporting the inner pipe 4, a cut out part 19A concaved directed from a left and right other side end part 5b of the joint 5 to a left and right center side of the joint is formed in the upper face side of the inner pipe supporting part 12, the front and rear fringe part 20A of the cut out part 19A is formed so as to move upward and move to a front and rear center as going from the left and right other side end part 5b of the joint 5 to the left and right center side of the joint 5, and is continuous to the outer face upper face of the joint 5 in the left and right center side of the joint 5, and the left and right other side end part 5b side of the joint 5 of the front and rear fringe part 20A of the cutout part 19A can be inserted into the gap 9 between the ring part inner hole 8 and the inner pipe 4 with the inner hole 8 upper end of the ring part 6 of the ring runner 2 coming into contact with the upper end of the inner pipe 4.