A remote controller includes a display part and an operation part. Since the display part switches plural kinds of specifications to display behavior and setting conditions of an air conditioner, plural kinds of specifications are prepared in the display part. From a central controller a communication part receives a command for air conditioning behavior of an air conditioner and switching of the display specification. The command includes packet for storing information which indicates switching of the display specification. As a result, the central controller can centrally and individually control both the air conditioning behavior of the air conditioner and switching of the display specification in the display part without operating the display part for each of the air conditioners from a distance.