PURPOSE: To reduce the consumption of power by a method wherein the execution of communication between control devices on the indoor and outdoor sides is possible and an air-conditioning control on the indoor side is executed by second means for various controls for air conditioning, while the air-conditioning control on the outdoor side is executed by a first control device on the outdoor side.

CONSTITUTION: An air-conditioning control on the indoor side is executed through second means 50-2 for various controls for air conditioning. The air-conditioning control on the outdoor side is executed by a first control device 20 on the outdoor side on the basis of transmission of control information to the first control device 20 on the outdoor side by communication between the first control device 20 on the outdoor side and a second control device 20-2 on the indoor side. The first control device 20 on the outdoor side generates necessary control signals on the basis of a command signal from the second control device 20-2 on the indoor side and signals of first means 40 for various inputs for air conditioning and outputs them to first means 50 for various controls for air conditioning on the outdoor side. It generates also the drive signal of a motor operated valve and drives a stepping motor 30. In the case when electrification is not needed, the power of a system of the first control device 20 of an outdoor machine is interrupted.