An air-conditioning device has a dust removing function, including: an outdoor air introducing portion for introducing outdoor air into a case; an outdoor air discharge portion having a blowing fan for supplying the indoor environment with the outdoor air introduced through the outdoor air introducing portion; an indoor air introducing portion for introducing indoor air; and an indoor air discharge portion having a blowing fan for discharging the indoor air introduced through the indoor air introducing portion into the outdoor environment, wherein the air-conditioning device includes: a filter coupled inside the entrance of the outdoor air introducing portion to be able to collect dust that is introduced together with outdoor air; and an opening formed through the lower end of the edge portion of the filter.