An air-conditioning system comprising: one or a plurality of outdoor units; a plurality of indoor units (A1, A2); and a control device provided with an outdoor unit control device,an indoor unit control device (41, 42), and a trial run control unit; wherein each indoor unit (A1, A2) includes an address setting device configured to set an address of each indoor unit (A1, A2), wherein the outdoor unit control device is configured to control each outdoor unit and the indoor unit control device (41, 42) is configured to control each indoor unit (A1, A2), wherein said control device and a plurality of devices among the outdoor units and the indoor units (A1, A2) are connected to each other through a communication medium, and transmission and reception of information is performed between the control device and said plurality of devices among the outdoor units and the indoor units (A1, A2), wherein the address setting device comprises setting means configured to set an address of each indoor unit (A1, A2) and that is provided with each indoor unit (A1, A2), and wherein the setting means is configured to set, in a case where a trial run is performed by the trial run control unit such that each outdoor unit is operated, a predetermined pulse command is input to an expansion valve of each indoor unit (A1, A2), and the expansion valve is opened to operate the indoor unit (A1, A2), a combination of a unique identification number of the outdoor unit which is operated and a value indicating a specification of the indoor unit (A1, A2) as the address of the indoor unit (A1, A2) of which the operation is confirmed by determining that an inlet refrigerant temperature in the indoor unit (A1, A2) is equal to or smaller than a predetermined temperature, or a pressure of a refrigerant sent to a compressor of the outdoor unit is equal to or smaller than a predetermined pressure and by performing confirmation of connection between the outdoor unit and the indoor (A1, A2) unit through a refrigerant pipe. one or a plurality of outdoor units; a plurality of indoor units (A1, A2); and a control device provided with an outdoor unit control device,an indoor unit control device (41, 42), and a trial run control unit; wherein each indoor unit (A1, A2) includes an address setting device configured to set an address of each indoor unit (A1, A2), wherein the outdoor unit control device is configured to control each outdoor unit and the indoor unit control device (41, 42) is configured to control each indoor unit (A1, A2), wherein said control device and a plurality of devices among the outdoor units and the indoor units (A1, A2) are connected to each other through a communication medium, and transmission and reception of information is performed between the control device and said plurality of devices among the outdoor units and the indoor units (A1, A2), wherein the address setting device comprises setting means configured to set an address of each indoor unit (A1, A2) and that is provided with each indoor unit (A1, A2), and wherein the setting means is configured to set, in a case where a trial run is performed by the trial run control unit such that each outdoor unit is operated, a predetermined pulse command is input to an expansion valve of each indoor unit (A1, A2), and the expansion valve is opened to operate the indoor unit (A1, A2), a combination of a unique identification number of the outdoor unit which is operated and a value indicating a specification of the indoor unit (A1, A2) as the address of the indoor unit (A1, A2) of which the operation is confirmed by determining that an inlet refrigerant temperature in the indoor unit (A1, A2) is equal to or smaller than a predetermined temperature, or a pressure of a refrigerant sent to a compressor of the outdoor unit is equal to or smaller than a predetermined pressure and by performing confirmation of connection between the outdoor unit and the indoor (A1, A2) unit through a refrigerant pipe.