PURPOSE: To get a well-adaptability of an air conditioning feeling and perform an accurate air conditioning control by a method wherein a deviation temperature during a heating operation is set lower than a deviation temperature during a cooling operation, a temperature varying width is set to a nearly equal value and when a temperature higher or lower than the deviation temperature is kept for a predetermined period of time, its ON/OFF control is carried out.

CONSTITUTION: A heating temperature and a cooling temperature are set to a set temperature TS1 and a set temperature TS2, respectively. Deviation temperatures DT1, DT2 (DT1<DT2) of the same temperature are set. A room temperature during a cooling operation is controlled to have a relation of TS1±DT1 and a room temperature during a heating operation is controlled to TS2±DT2. The reason why the relation of DT1<DT2 is set is that a heating temperature T1 and a cooling temperature T2 detected by a temperature sensor correspond to actual room temperatures TR1 and TR2 added with a heating temperature ΔT of a substrate in a sensor. Under this influence, varying ranges TZ1 and TZ2 of the room temperatures TR1 and TR2 to be controlled are different and a varying width TZ1 during a heating operation is increased more than that during a cooling operation. Due to this fact, it is necessary to change the value of DT in response to a varying range. The DT value during the heating operation is reduced below the value during the cooling operation In this case, if the values T1 and T2 are out of the reference time, the damper is opened or closed.