To solve the conventional problem that long-time continuous operation of humidifying work by use of a refrigeration cycle using hot gas causes a mechanical or functional failure in a refrigerator (compressor), which disables satisfactory temperature control of an object of temperature conditioning by proper cooling or heating.

This temperature control device is adapted to circulate the hot gas discharged from a freezer by directly introducing it to a heat exchanger through a selector valve in heating, introducing the refrigerant gas in an imperfectly condensed state passed through the heat exchanger to the primary side of a high-efficiency heat exchanger self-generating a cycle through a selector valve, distributing the refrigerant gas passed through the primary side to the secondary side of this heat exchanger through an expansion valve, and returning the refrigerant gas passed through the secondary side to the freezer.