To provide a liquefied gas supply device in which vaporized gas is recovered, re-condensed and obtained liquefied gas is supplied to a cryostat under a gravity-free environment.

The liquefied gas supply device comprises a gas recovery pipeline 10b for recovering the gas vaporized in the cryostat 1, a re-condensing means 12 connected to the gas recovery pipeline 10b to cool and re-condense and liquefy the gas, a supply pipeline 10h connected to the re-condensing means 12 to feed the liquefied gas produced by the re-condensing means 12 to the cryostat 1, a first phase separating means 11 connected to the gas recovery pipeline 10b to separate the vaporized gas from the liquefied gas derived from the cryostat 1 and feed only the gas to the re-condensing means 12 through the gas recovery pipeline 10b, and a second phase separating means 18 connected to the supply pipeline 10h to separate the vaporized gas from the liquefied gas and supply only the liquefied gas to the cryostat 1.