Air-conditioning system

In the present invention, an air-conditioning system (1) has a plurality of air conditioners (2a, 2b, 2c, 2d) installed on a wall or on a ceiling, and an air-conditioning assistance device (4) installed at a position set away by an identical distance from each of the plurality of air conditioners (2a, 2b, 2c, 2d) on the wall or the ceiling. The air-conditioning assistance device (4) has: a thermal image sensor (41); an assistance-side communication unit (42) for receiving information relating to the operation state of some or all of the plurality of air conditioners (2a, 2b, 2c, 2d) from some or all of the plurality of air conditioners (2a, 2b, 2c, 2d), and transmitting a command for performing air-conditioning to some or all of the plurality of air conditioners (2a, 2b, 2c, 2d); a storage unit (43) for storing information obtained by the thermal image sensor (41) and information received by the assistance-side communication unit (42); and a processing unit (44) for analyzing the information obtained by the thermal image sensor (41) and the information received by the assistance-side communication unit (42) and generating a command.