Air purifier

Provided is an air purifier capable of reducing the time required to purify the interior of a room without causing discomfort to the occupants of the room. When an air purifier (1) is operating, the air taken into a casing (2) from an inlet (3) is purified by a purifying device (7), and the air is blown out to the exterior from an outlet (4). A controlling device (12) performs air flow maintenance control when a specific operation mode in which a user of the air purifier (1) specifies the air flow rate is selected. With air flow maintenance control, air speed is changed by an air guiding device (8) based on the state of pollutant detection while in a state in which the flow rate of air blown out from the outlet (4) by the blowing device (5) is maintained to be constant. Or the air speed is changed by the air guiding device (8) and the air volume is changed by the blowing device (5). Thus, the efficiency of removing dust can be improved, the comfort of the user can be maintained, and the time required for purifying the room can be reduced without causing the room occupants to feel that air is being blown on them.