PURPOSE: To suppress pressure rise on the discharging side of a compressor by a method wherein a control device is comprised of means for setting a target speed of the compressor during a heating operation, means for setting a suitable speed, and means for lowering the pressure rise control starting pressure based on the difference between the target speed and the suitable speed.

CONSTITUTION: An air conditioner is provided with a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a capillary tube 4 and an indoor heat exchanger 5. During a heating operation, the outdoor heat exchanger 3 acts as an evaporator, the indoor heat exchanger 5 is operated as a condenser. Refrigerant passes from the compressor 1 through the four-way valve 2 and the indoor heat exchanger 5 or the like and returns to the compressor 1. A target speed during starting of the compressor 1 when the heating operation is started and the suitable speed for a safe operation are compared to each other. When the difference between the target speed and the suitable speed is higher than the predetermined value, the pressure rise restricting control starting pressure is lower than that of the normal case and then the high pressure increasing state is superiorly restricted.