PURPOSE: To secure more safety and to reduce size by mounting a closing valve on a compression spring, a self-adjustable ring, an O-ring seal and a guide ring in the bottom part, and forming this as a guide and a fastener of an opening/closing and adjusting compression spring in order.

CONSTITUTION: An automatic opening, dosing and closing valve is formed of a valve element 1 housing a closing valve 2 on an O-ring seal 3 in the inside. The valve 2 is mounted on a bottom guide 7, and is pressed in an opening state and a closing state by a spring 4, a self-adjustable ring 5 and the O-ring seal 6. Fluid is flowed through a top opening passage 8 of the top upper part of the valve element 1 and a series of another bottom opening passage 9 on the bottom guide 7.