Provided are an air-conditioner and a controlling method thereof. The air-conditioner includes a blower fan forcibly generating a flow of air, a filter disposed on a flow path of the air that forcibly flows by the blower fan, and a vibration actuator disposed on a side of the filter. The method for controlling an air-conditioner includes disposing a collection part under a filter of an air-conditioner, vibrating a vibration actuator disposed on a side of the filter, and separating the collection part from a lower side of the filter.