PURPOSE: To provide a high-temperature treatment apparatus capable of utilizing the thermal energy in high efficiency, by using a heating circuit having a heating device and a heat-dissipating cooling circuit having a heat-exchanger.

CONSTITUTION: The hot water W in the tank 10 is heated or cooled by the heating circuit 20 or the heat-dissipating cooling circuit 30, and sprayed through the sprayers 15 attached to the upper part of the tank 10 to effect the heating or cooling of the object to be treated. In the heating stage, the heating circuit 20 is made, and the hot water in the tank is heated with the steam heater 23 and sprayed through the sprayers 15. In the cooling stage, the heat-dissipating cooling circuit is made, and the cold water cooled with the heat-exchanger 33 is sprayed through the sprayers 15. The heat recovered by the heat-exchanger is utilized to the preheating of the object by the preheater 40. The apparatus can be used for the retort sterilization of foods, etc.