CONTROL METHOD FOR VEHICLE AIR CONDITIONING, AND VEHICLE AIR CONDITIONING DEVICE

A vehicle air-conditioning device is provided for controlling a vehicle air-conditioning of a vehicle in accordance with a control method. A negative pressure, which is generated in an intake passage of the internal combustion engine by a vacuum servo that assists a brake pedal force, is estimated based on an atmospheric pressure and a pressure inside the intake passage. When a predetermined condition is established that includes a state in which the estimated negative pressure inside the vacuum servo is insufficient relative to a predetermined pressure during operation of the air-conditioning compressor, the air-conditioning compressor is stopped during a first time period, the air-conditioning compressor is operated during a second time period regardless of the predetermined condition after the first time period has elapsed, and operation of the air-conditioning compressor is controlled in accordance the states of the predetermined condition being established after the second time period has elapsed.