Abstract: An air conditioning for a room of a high-rise building, for example, is carried out in consideration of the difference in temperatures in a central interior zone and a circumferential perimeter zone of the room changeably to heating and cooling in accordance with an operation mode and a room temperature set point. In the actual air conditioning, a room temperature in the interior zone is first set and an actual room temperature in the perimeter zone is detected. The set room temperature in the interior zone is compared with the detected room temperature in the perimeter zone to thereby select an operation mode (heating or cooling) of air conditioning of the perimeter zone by an operation mode selecting unit.