A control device that controls a plurality of air conditioners includes a data memory section for storing performance model data representing the relationship between air conditioning capability and power consumption for each of the plurality of air conditioners. An overall air conditioning load calculating section calculates an overall load that is the sum of air conditioning loads of the plurality of air-conditioning apparatuses. An air conditioning capability allocation calculating section an air conditioning capability for each of the plurality of air conditioners on the basis of the performance model data and the overall load so that the sum of the air conditioning capability of the plurality of air conditioners is the overall load and the sum of the power consumption of the plurality of air conditioners is minimum. A control signal section sends a control signal related to the air conditioning capability to each of the plurality of air conditioners.