Abstract: Four air flow control doors of an automotive air conditioning device are synchronously controlled by a link mechanism. With a unique construction of the link mechanism, the following advantageous results are obtained. In a ventilation mode of a maximum cool condition, sufficient amount of cooled air can be blown into the vehicle cabin from a ventilation opening. In the ventilation mode of a half-hot condition, mixing of cooled air and warmed air is effectively carried out before being blown into the vehicle cabin. In a bi-level mode of the half-hot condition, the passengers in the vehicle cabin can enjoy a so-called "lower side warming and upper side cooling" air conditioning wherein the lower portion of the vehicle cabin is suitably warmed and the upper portion of the vehicle cabin is suitably cooled.