An air conditioner having a dust removing device which enables dust having stuck to its filters to be automatically removed without fail and prevents the removed dust from sticking again to the filters is to be provided. It is equipped with a sliding device 6 (motor 6) for sliding in a prescribed direction filters 5 arranged between an air intake port 121 and a heat exchanger 3, and with cleaners 7 to remove dust having stuck to the filters 5, automatically cleans the filters 5 and prevents the removed dust from being brought out of the cleaners 7.