To allow installation of a valve with expansion joint by simple work in a narrow space incapable of arranging an expansion pipe.

This valve is provided with the first fixing bolt.nut means by which a short pipe 29 is fixedly joined to the outside of a valve flange 25 joined to a pipe flange 27 in piping 26, wherein a movable flange 30 and a seal pressing flange 31 are arranged loosely engagedly with the short pipe 29 to be movable along an axial center direction of the short pipe 29, so as to attach an O-ring 32 by being pressed between the flange 30 and the flange 31, and which connection-fixes the pipe flange 27, the movable flange 30 and the seal pressing flange 31, and the second fixing bolt.nut means for connection- fixing the valve flange 25, the pipe flange 27, the movable flange 30 and the seal pressing flange 31.