When an idle stop is determined to be immediately imminent, an air conditioner ECU (5) executes a front-seat air conditioning mode even when it has been determined that a occupant-concentrated air conditioning mode can be executed. In this manner, opening and closing mechanisms (48 to 53) are controlled so that conditioned air is blown out from driver's seat side air outlets (57, 61, and 67) and conditioned air is blown out from a passenger seat side foot air outlet (63). Therefore, it is possible to prevent the temperature of the air blowing into an internal air inlet (14c) from increasing when an idle stop occurs during cooling, and thus it is possible to prevent the temperature of the air blowing out from an outlet into a vehicle interior space from increasing. In other words, it is possible to prevent the temperature in the vehicle interior space from changing when a driving engine (4) is stopped due to an idle stop.