An air conditioning system comprising: an air conditioning apparatus configured to perform cooling or heating of a target space by circulating refrigerant; and a refrigerant leakage detector to be installed in the target space, the refrigerant leakage detector being configured to detect refrigerant leakage from the air conditioning apparatus to the target space, the air conditioning apparatus including a plurality of indoor units (20a, 20b), and at least one outdoor unit (10a, 10b), the air conditioning system further comprising a plurality of respective refrigerant leakage suppression devices (70a, 70b) provided corresponding to the plurality of indoor units, each of the plurality of refrigerant leakage suppression devices being configured to suppress the refrigerant leakage from a corresponding indoor unit when the refrigerant leakage from the corresponding indoor unit is specified, characterized in that each of the plurality of indoor units is associated with the refrigerant leakage detector, the air conditioning system further comprises a controller configured to perform a process for specifying an indoor unit in which the refrigerant leakage has occurred when the refrigerant leakage is detected by the refrigerant leakage detector, the controller is configured to operate a refrigerant leakage suppression device included in the plurality of refrigerant leakage suppression devices and provided correspondingly to the indoor unit specified by performing the process when the refrigerant leakage is detected by the refrigerant leakage detector, wherein the process includes a process for (i) calculating a degree of supercooling of the refrigerant at an outlet of the outdoor unit corresponding to a target indoor unit, and (ii) specifying, based on an amount of decrease of the calculated degree of supercooling from a degree of supercooling in a normal state, an indoor unit in which the refrigerant leakage has occurred, the degree of supercooling in the normal state being prepared in advance. an air conditioning apparatus configured to perform cooling or heating of a target space by circulating refrigerant; and a refrigerant leakage detector to be installed in the target space, the refrigerant leakage detector being configured to detect refrigerant leakage from the air conditioning apparatus to the target space, the air conditioning apparatus including a plurality of indoor units (20a, 20b), and at least one outdoor unit (10a, 10b), a plurality of indoor units (20a, 20b), and at least one outdoor unit (10a, 10b), the air conditioning system further comprising a plurality of respective refrigerant leakage suppression devices (70a, 70b) provided corresponding to the plurality of indoor units, each of the plurality of refrigerant leakage suppression devices being configured to suppress the refrigerant leakage from a corresponding indoor unit when the refrigerant leakage from the corresponding indoor unit is specified, characterized in that each of the plurality of indoor units is associated with the refrigerant leakage detector, the air conditioning system further comprises a controller configured to perform a process for specifying an indoor unit in which the refrigerant leakage has occurred when the refrigerant leakage is detected by the refrigerant leakage detector, the controller is configured to operate a refrigerant leakage suppression device included in the plurality of refrigerant leakage suppression devices and provided correspondingly to the indoor unit specified by performing the process when the refrigerant leakage is detected by the refrigerant leakage detector, wherein the process includes a process for (i) calculating a degree of supercooling of the refrigerant at an outlet of the outdoor unit corresponding to a target indoor unit, and (ii) specifying, based on an amount of decrease of the calculated degree of supercooling from a degree of supercooling in a normal state, an indoor unit in which the refrigerant leakage has occurred, the degree of supercooling in the normal state being prepared in advance.