To realize stable pressure feeding of liquid to be conveyed at every predetermined quantity and to prevent occurrence of a fault from occurring.

A liquid pressure feeding apparatus includes first and second pumps 21, 22 which suck a liquid carbon dioxide into a cylinder 23 in a gas cylinder 41 as a piston 24 is raised, and which discharge the liquid carbon dioxide in the cylinder 23 from a discharge port 27 as the piston 24 is lowered. When the pumps 21, 22 discharge, compressed air is supplied from a first air port 31 of a driver cylinder 29, and the piston 24 is lowered by an air pressure. On the other hand, when the pumps 21, 22 suck, the first air port 31 communicates with an exhaust tube 50, the piston 24 is raised by supply pressure of the liquid carbon dioxide. An exhaust gas flow rate from the first air port 31 of the driver cylinder 29 is controlled by speed controllers 49, 54, and the raising speed of the piston 24 is controlled.

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