Provided is a device for re-liquefaction of a liquefied gas, which can be compactly structured and easily handled. The device (1) for re-liquefaction of BOG vaporized from LNG in a cargo tank (3) comprises a refrigerator group (20) for liquefying nitrogen, which is provided in a secondary refrigerant circulating passage (24) in which a nitrogen having a condensation temperature lower than that ofBOG is circulated, a conveyance pump (22) for conveying a liquid nitrogen cooled by the refrigerator group (20) through the secondary refrigerant circulating passage (24), and a heat exchanger (12) which is provided in the secondary refrigerant circulating passage (24) and exchanges heat between the liquid nitrogen conveyed by the conveying pumps (22) and BOG to condense and liquefy BOG. The heatexchanger (12) is installed near the cargo tank (3).