<p>A valve (10) has a contact part (14) that comes in contact with a valve body (12) and restricts the rotation of the valve body (12) when the valve body (12) is switched from a first state to a second state. The contact part (14) is formed into the shape of a protuberance or a platform by a method such as welding to the inner wall of a case (11). The contact part (14) is provided so as to come in contact only with an area of the valve body (12) near a valve rod (13) which is a rotating shaft, and not come in contact with areas farther away from the valve rod (13) than the area near the valve rod (13).</p>
