To provide an air cleaner utilizing secondarily generated ozone effectively, safely and steadily.

An air purifier is equipped with the blow fan 3 provided in a wind channel 2, the dust removing filter 1 provided on the suction side of the blow fan 3, the discharge element 4 provided on the exhaust side of the dust removing filter 1, a dust collection part 5 electrically collecting dust charged by the discharge element 4, an ozone deodorizing/decomposing catalyst 6 decomposing ozone generated from the discharge element 4 and a malodorous component in air, an ozone sensor 7 for controlling the concn. of ozone passed through the ozone deodorizing/decomposing catalyst 6 and a control circuit 8.