Provided is an air purifier capable of improving the cleaning effect. The housing 2 that opens the suction port 3 and the air outlets 4 and 5, the air passage 8 that connects the air inlet 3 and the air outlets 4 and 5, the blower 10 disposed in the air passage 8, and the air inlet 3 In the air cleaner 1 provided with the prefilter 6 disposed facing the surface, the cleaning device 30 that cleans the prefilter 6, and the dirt sensor that detects the degree of dirt in the air, the air filter 1 for each predetermined first period. An automatic cleaning mode for driving the cleaning device 30 at the first cleaning time is provided, and the cleaning device 30 is driven when the degree of contamination in the air satisfies a stop condition larger than a predetermined value within a predetermined period immediately before the first cleaning time. Is prohibited.清浄効果を向上できる空気清浄機を提供する。吸込口３及び吹出口４、５を開口する筐体２と、吸込口３と吹出口４、５とを連結する空気通路８と、空気通路８内に配される送風機１０と、吸込口３に面して配されるプレフィルタ６と、プレフィルタ６を清掃する清掃装置３０と、空気中の汚れ度を検知する汚れセンサとを備えた空気清浄機１において、所定の第１周期毎の第１清掃時期に清掃装置３０を駆動させる自動清掃モードを設け、第１清掃時期の直前の所定期間内で空気中の汚れ度が所定値よりも大きい停止条件を満たした時に清掃装置３０の駆動を禁止する。
