To surely seat a disklike valve element to an annular valve seat by preventing the tilt or displacement in a radius direction of the disklike valve element.

An inlet 4 and an outlet 5 are formed by a valve casing composed of inlet and outlet side members 1 and 2, to provide an annular valve seat 6 between the inlet 4 and the outlet 5. A disklike valve element 7 is arranged in the inlet 4 side of the valve seat 6 to fix a sleeve 8 sliding in the inner periphery of the valve seat 6 to the valve element 7. A tensile coil spring 10 for energizing the valve element 7 in a valve-open direction is arranged between a spring bearing 9 fixed to the sleeve 8 and the valve seat 6. A valve hole 11, for communicating the inlet 4 and outlet 5 sides when the valve element 7 is separated from the valve seat 6, is formed on the sleeve 8.