PROBLEM TO BE SOLVED: To provide an air conditioning system that humidifies conditioned air during air conditioning operation, and achieves sterilization operation using functional water when there is a need to sterilize a humidifying element in an air conditioner.SOLUTION: An air conditioning system 10A performs first air conditioning operation in which a humidifying element 22 humidifies the conditioned air produced by an air conditioner 12 when measured humidity has not reached set humidity. When the measured humidity reaches the set humidity, the system performs second air conditioning operation in which supply of humidifying water from a humidifying water supply line 13 to the humidifying element 22 is stopped and the conditioned air produced by the air conditioner 12 is supplied to an air-conditioning room 11. In sterilizing bacteria grown in the humidifying element 22, the system performs sterilization operation in which supply of humidifying water from the humidifying water supply line 13 is stopped and functional water stored in functional water storage tanks 39, 41 is supplied to the humidifying element 22 for a predetermined time.
