To provide a new energy-saving air conditioning system, condensing a desiccant to a suitable and low concentration with as smaller energy as possible, and keeping the humidity in a room to a target humidity by the above low-concentration desiccant.

This air conditioning system includes: a condensing device 15 for adjusting the desiccant D to a moderate concentration; and an air cooling device 13 for cooling the air in a room. A vacuum condensation device is applied to the condensing device 15, and the desiccant D controlled to a suitable concentration is directly sprayed to the air cooling device 13, and the desiccant D and cooled air are cooled to suitable temperature, whereby the room temperature and the humidity are simultaneously controlled so that even at a high room temperature, comfortable air-conditioning is achieved and the evaporating temperature is set to a higher temperature.