Abstract: Provided is a device for implementing a space environment. More specifically, in order to implement a space environment, while a shroud is disposed inside a vacuum container, an internal pressure of the shroud is controlled to adjust a saturation temperature of working fluid by forming a closed system including a cryogenic refrigerator. As a result, the environment can be implemented at a required temperature. At this time, the pressure can be adjusted by supplying room-temperature gas as working fluid into the closed system, which may result in costs being reduced because there is no need to manage a liquid bombe, and the working fluid injected inside can be used in a recycled manner.