Abstract: An air conditioner for reduction of energy consumption without impairing the comfortable feeling, which comprises a room temperature detector for detecting the room temperature of an air-conditioned room, temperature setting apparatus for setting a target temperature, air conditioning device for performing an air conditioning operation to bring the room temperature detected by the room temperature detector toward the target temperature, and target temperature charger, which corrects the target temperature to rise and fall periodically in accordance with a predetermined rule after the room temperature has substantially reached the target temperature through use of the air conditioning devices. The charger shifts the average value of the target temperature after the start of the correction in such a direction that the air conditioning load of the air conditioning device is reduced from that for attaining the target temperature before the correction.