AIR PURIFIER

Provided is an air purifier capable of sufficiently cleaning a filter. This air purifier 1 comprises: a housing 2 having a suction port 3 and blowout ports 4, 5 opened; an air passage 8 which connects the suction port 3 and the blowout ports 4, 5; an air blower 10 which is disposed within the air passage 8; a prefilter 6 which is disposed so as to face the suction port 3; and a cleaning device 30 which cleans the prefilter 6. The cleaning device 30 has: a supply roll 40 around which the sheet-like prefilter 6 is wrapped; a wind-up roll 50 which winds up the prefilter 6; a drive motor 100 which rotationally drives the wind-up roll 50; a biasing unit 70 which biases the rotary shaft of the supply roll 40 in the opposite direction from the wind-up direction during the wind-up of the wind-up roll 50; a brush body 80 which slides against the prefilter 6 when the wind-up roll 50 is rotating; and a rotational amount detection unit 110 which detects the rotational amount of the drive motor 100. The loss of synchronization of the drive motor 100 is determined on the basis of the detection result of the rotational amount detection unit 110, and the drive motor 100 is inverted upon losing synchronization.