Abstract: On each refrigerant piping to an indoor heat exchanger of each indoor unit, there is provided a flow control valve of which target opening (.theta.t) is selected separately according to an air-conditioning load of each indoor unit. Provided, the flow control valve which will have a maximum target opening (.theta.t.sub.max) selected, is fully opened, with the remaining flow control valves having such an opening greater than each of respective target openings (.theta.t) by a given value (.DELTA..theta.). Meanwhile, a target frequency (Ft) of output power from an inverter is selected, following the total of air-conditioning loads of respective indoor units; provided, an actual frequency (F) of output power of the inverter is selected in such a value lower than the target frequency (Ft) by a given value (.DELTA.F).