Air conditioner

An air conditioner having a refrigerating cycle in which at least a refrigerant compressor driven by an electromotive element, a heat source side heat exchanger, a pressure reducing unit and a utilization side heat exchanger are circularly connected via a refrigerant piping line, these constituent elements of the refrigerant cycle being divided and disposed in an indoor side unit and an outdoor side unit, the indoor side unit being provided with a motor which drives an air blowing fan of the utilization side heat exchanger, a power to drive the motor being supplied via the outdoor side unit,

• wherein the indoor side unit is connected to the outdoor side unit via three lines comprising a first power line and a second power line through which an alternating current flows and a signal line through which a signal is transmitted by using one of the power lines as a common use line, a commercial alternating-current power is applied to the first power line and the second power line in the outdoor side unit, the outdoor side unit includes a current detector which detects, from this commercial alternating-current power, the alternating current flowing through one of the first power line and the second power line, a switch which performs a circuit communicating operation in a case where a current value detected by this current detector exceeds a predetermined standard value, and an outdoor side control circuit to which the commercial alternating-current power is supplied via this switch to control the driving of the electromotive element, the indoor side unit includes an indoor side control circuit which controls the supplying, to the motor, of the commercial alternating-current power obtained via the first power line and the second power line, and this indoor side control circuit starts the driving of the motor in response to the start of an air conditioning operation, and transmits and receives the signal to and from the outdoor side control circuit of the outdoor side unit via the signal line after driving the motor.