An air conditioner comprising: one outdoor main unit having at least one variable-capacity compressor (11, 12); a plurality of outdoor sub-units (1b, 1c) having at least one variable-capacity compressor (13, 14, 15, 16); a plurality of indoor units (2a, 2n); a first detection section configured to detect a sum n, of demand capacities of the indoor units (2a, 2n); a second detection section configured to detect a sum F(a) of maximum capacities F(i) of the respective variable-capacity compressors (11, 12, 13, 14, 15, 16); a calculation section configured to detect a ratio n/F(a) of the sum demand capacity n which is detected by the first detection section to the sum maximum capacity F(a) which is detected by the second detection section: a decision section configured to decide whether or not the ratio n/F(a) calculated by the calculation section is below a set value Q; a setting section configured to set a higher efficiency operation mode when a result of decision by the decision section is affirmative and a normal operation mode when a result of decision by the decision section is negative; a first control section configured to, when the higher efficiency operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with a capacity lower by a predetermined value than their maximum capacity as an upper limit capacity; and a second control section configured to, when the normal operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with their maximum capacity as an upper limit capacity. one outdoor main unit having at least one variable-capacity compressor (11, 12); a plurality of outdoor sub-units (1b, 1c) having at least one variable-capacity compressor (13, 14, 15, 16); a plurality of indoor units (2a, 2n); a first detection section configured to detect a sum n, of demand capacities of the indoor units (2a, 2n); a second detection section configured to detect a sum F(a) of maximum capacities F(i) of the respective variable-capacity compressors (11, 12, 13, 14, 15, 16); a calculation section configured to detect a ratio n/F(a) of the sum demand capacity n which is detected by the first detection section to the sum maximum capacity F(a) which is detected by the second detection section: a decision section configured to decide whether or not the ratio n/F(a) calculated by the calculation section is below a set value Q; a setting section configured to set a higher efficiency operation mode when a result of decision by the decision section is affirmative and a normal operation mode when a result of decision by the decision section is negative; a first control section configured to, when the higher efficiency operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with a capacity lower by a predetermined value than their maximum capacity as an upper limit capacity; and a second control section configured to, when the normal operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with their maximum capacity as an upper limit capacity. a decision section configured to decide whether or not the ratio n/F(a) calculated by the calculation section is below a set value Q; a setting section configured to set a higher efficiency operation mode when a result of decision by the decision section is affirmative and a normal operation mode when a result of decision by the decision section is negative; a first control section configured to, when the higher efficiency operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with a capacity lower by a predetermined value than their maximum capacity as an upper limit capacity; and a second control section configured to, when the normal operation mode is set, allow the respective variable-capacity compressors (11, 12, 13, 14, 15, 16) to be operated with their maximum capacity as an upper limit capacity.