To stabilize the liquid seal performance as well as the response speed and prevent the sticking to a valve seat.

When closing a valve, a lift transmitter 44 is pushed by revolution of a cam 16 and a diaphragm 40 bends via a sphere 48 and a component 44a for alignment which closes a liquid inlet of the valve seat 34. And when opening the valve, the lift transmitter 44 is returned by revolution of the cam 16 and the biasing force of a coil spring 46 and the bending of the diaphragm 40 is returned which opens the liquid inlet of the valve seat 34.