To provide a refrigeration system capable of considerably improving the efficiency and durability of a refrigerating cycle by efficiently cooling a high temperature part of a compression refrigerating machine to a desired state, and shifting a working region to a lower temperature region by cooling.

The refrigeration system is formed as a closed circuit filled with liquid and having an evaporating section and a condensing section for the liquid to cool the high temperature part of the compression refrigerating machine, and is provided with a thermal siphon for repeating a cycle of movement and phase change of the liquid in the closed circuit so that, after the liquid in the evaporating section receives heat and is evaporated, it is liquefied by heat radiation in the condensing section and returned to the evaporating section.