COMPRESSOR UNIT

A compressor unit includes a compression stage that compresses hydrogen gas as boil-off gas from a liquid hydrogen storage tank. The compression stage includes a cylinder unit, a piston, a piston rod that connects the piston to a crank mechanism, a cover part disposed outside the cylinder unit, a nitrogen gas supply unit that supplies nitrogen gas to a heat insulation space between the cover part and the cylinder unit, and a control unit that controls the nitrogen gas supply unit so that nitrogen gas is supplied into the heat insulation space while the compression stage compresses hydrogen gas.