PURPOSE: To provide an air conditioner for a vehicle which can select so that either one of ventilating resistance and dust collecting performance is made large according to its necessity and the other is made small.

CONSTITUTION: An air filter device 4 is interposed in the vicinity of a blower unit side duct butting part 3 in a cooling unit case 2, and the air filter device 4 has an upper filter frame 10 locked inside of the cooling unit case 2 and a lower filter frame 20 which is arranged inside of the cooling unit case 2 and is installed vertically movably freely on the upper filter frame 10, and is formed of a regulating member to control a position of the lower filter frame 20 and a bellows shape filter 40 which is supported by the respective upper and lower end parts of the upper filter frame 10 and the lower filter frame 20 and projects longitudinally so as to be vertically extensible and contractible freely.