In an air-conditioner control unit, when pollen mode control is set by a vehicle occupant to perform the pollen mode control that can provide a defogging effect while maintaining the pollen removal effect, the opening of an air inlet door is forcibly set to an inside-air introduction mode (S330) when the following two conditions hold: ambient temperature Tam is higher than a threshold (5 to 6° C.) set in a low-temperature region (S320), and a compressor system is able to operate normally without causing an abnormal pressure (S330). If even one of these conditions does not hold, the opening of the air inlet door is not forcibly set to the inside-air introduction mode, and the air inlet door is operated as in normal control. In this way, in the pollen mode control, since the pollen removal effect in the inside-air introduction mode is enabled only when the ambient air is relatively high, the occurrence of windshield fogging can be suppressed.