PURPOSE: To enable a suitable operation mode to be selected in response to an entire load by a method wherein capability points determined in reference to set temperatures at a plurality of air conditioned places and an indoor temperature are divided into a cooling capability point and a heating capability point and then either a cooling mode or a heating mode having a larger total value of each of the number of points is selected.

CONSTITUTION: Either a cooling mode or a heating mode is selected in respect to a remote controller 11 for each of air conditioned locations and a required room temperature is set. Each of the remote controllers 11 may define a cooling capability point and a heating capability point in reference to a difference between a room temperature Ta and a set temperature Tt and send the type of operation mode and the signals corresponding to the number of points to a main control circuit 8. In the main control circuit 8, the number of points are added for every kind of operation mode and set to get a sum. Total numbers are compared and either a cooling operation mode or a heating operation mode having a larger number of points is selected and its operation is changed over.