The first cold air flow door 26 and the first hot air flow door 24 for adjusting the blowout air temperature are arranged in the first air passage, and the second cold air flow door 27 and the second hot air flow door 25 for adjusting the blowout air temperature are arranged in the second air passage. When a larger target air flow volume between the target air flow volume on the first air passage side and the target air flow volume on the second air passage side is selected so as to determine an air flow volume of the blower, in an air passage to which the smaller target air flow volume is applied, while the ratio of the cold air flow volume to the hot air flow volume is being maintained constant, the passage opening area is throttled by the cold air flow door and the hot air flow door.