An air conditioner includes a refrigerant circuit configured to interconnect a heat source unit and a utilization unit, a transmission line that exchanges a signal between the heat source unit and the utilization unit, an information obtaining section, an operation controlling section capable of performing a refrigerant quantity judging operation, a refrigerant quantity judging section, and a condition setting section. The information obtaining section obtains information on the utilization unit connected to the heat source unit via the transmission line. The refrigerant quantity judging section judges the adequacy of the refrigerant quantity in the refrigerant circuit by using the operation state quantity of constituent equipment or refrigerant flowing in the refrigerant circuit in the refrigerant quantity judging operation. The condition setting section sets a condition for the refrigerant quantity judging operation according to the information on the utilization unit obtained by the information obtaining section.