An automatic-filling valve unit has a nozzle disposable within the neck of a container and a flow control valve is located on the lower end of said nozzle for quick shutoff. The valve is opened by air pressure and closed by a spring. Vacuum is drawn through the lower end of the nozzle constantly while filling of a container progresses and is interconnected to a control valve for the air pressure which operates the flow control valve, whereby when liquid rising in the container reaches the suction inlet on the nozzle, the control valve is actuated to release the air pressure instantly and permit the spring to close the flow control valve.