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 connectsthe 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 30which 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 whichrotationally 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 synchronizati