AIR-CONDITIONING DEVICE FOR VEHICLE

PURPOSE:To prevent entrance of exhaust gas to a car as regular control of air- conditioning is executed by varying a switching timing according to a car speed, in an air-conditioning device wherein switching of an air-conditioned air introduction mode to an internal air introduction mode according to gas concentration in the open air or internal air is controllable. CONSTITUTION:A mode switching control means 4a which receives an output from a gas sensor 72 and through the working of which a mode switching means 30 is controlled so that switch to an internal air introduction mode is executed when gas concentration exceeds a given threshold is provided. In addition to the mode switching control means, a mode switching timing varying means 4b by means of which a timing of switch to an internal air introduction mode with the aid of a mode switching means 30 is advanced when a car speed exceeds a given reference speed is provide. Namely, a switching timing is varied through switching of a threshold according to a case where a car speed is high and a case where the car speed is low. When a car speed is below a reference car speed, entrance of exhaust gas to a car is prevented from occurring as regular control of air-conditioning is carried out. When it exceeds the reference speed, a switching timing is advanced to prevent entrance of quantities of exhaust gas.