An air conditioning device for a vehicle, provided with: an air blower unit having a first introduction path and a second introduction path through which inside air or outside air is sucked into an upper fan and a lower fan by switching between switching doors; and an air conditioning unit for discharging air into the vehicle interior. The air conditioning device for a vehicle is characterized in that the first introduction path is an introduction path into which only the outside air is introduced when the inside air and the outside air are sucked separately and in that an outside air amount adjustment mechanism for limiting the amount of delivery of the outside air according to the speed of the vehicle is provided in the first introduction path or at a position downstream thereof to reduce the generation of wind noise at a defroster opening or a face opening.