To provide a liquid force feed device capable of surely closing an exhaust valve port by an exhaust valve element.

This device is constituted so that a sealed vessel 4 is provided with a hydraulic fluid introducing port 9, a hydraulic fluid discharge port 5, a liquid inflow port 6 and a liquid discharge port 7; an air supply valve element 22 for opening and closing an air supply valve port 20 of the hydraulic fluid introducing port 9 and an exhaust valve element 19 for opening and closing an exhaust valve port 21 of the hydraulic fluid discharge port 5, are moved in a snap in response to the height of a liquid level of liquid gathered in the sealed vessel 4; the liquid is made to flow in from the liquid inflow port 6 by closing the air supply valve port 20 by opening the exhaust valve port 21 in the beginning; the liquid gathered in the sealed vessel 4 is forcibly fed from the liquid discharge port 7 by opening the air supply valve port 20 by closing the exhaust valve port 21 in the next place; and the exhaust valve port 20 arranged on the side of the exhaust valve element 19 on a side surface of the exhaust valve element 19, is opened and closed by opening the air supply valve element 22 by the exhaust valve element 19.