A valve body 3 is provided at its one side with a part for receiving an operation tool which turns a valve spindle, the valve body further provided at the other side with a part for mounting a connection tool 8 by which an external piping is attached and detached, and the valve body 3 moreover provided at the middle with a part 33 having a non-round cross section and a part 34 concaved from the outside surface of the part 33. A support member 4 consists of an engaging section 43 which engages with the part 33 to restrict or prevent the valve body 3 from turning and shifting in position, and an engaging section 44 which engages with the part 34 to restrict or prevent the valve body 3 from axially shifting in position.