A blower motor control for an air conditioner is carried out so that when a detected actual rotation speed has come into an allowable deviation range to a target rotation speed at the time of controlling the motor so as to approach its rotation speed to the target rotation speed, the output for adjusting the rotation speed is not changed. As a result, a stable rotation speed can be obtained as long as the load on the motor does not fluctuate. Furthermore, after the output has been fixed, the allowable deviation range is expanded to prevent the output from changing even if slight load fluctuation is caused. This allows stable controls.