The purpose of the present invention is to provide an air cleaner that controls increases in electricity consumed and noise and can sufficiently eliminate fine particles in air. Provided is an air cleaner (1) that is provided with a blown air passage (8) linking a suction inlet (3) for sucking in air and discharge openings (4, 5) for discharging air, a blower (10) disposed within the blown air passage (8), a filter unit (9) provided in the blown air passage (8) for collecting dust in the air and a dust sensor for detecting dust in the air, and that varies the rotational speed of the blower (10) to a plurality of different blower levels on the basis of a plurality of degrees of contamination divided into ranks according to concentrations of dust and sets the blower level to a higher rotational speed when the degree of contamination is high than when the same is low, wherein the concentration of fine particles smaller than a prescribed particle size that are included in the dust in the air is extracted from detection results from the dust sensor, and when the concentration of fine particles is higher than the prescribed degree of contamination, the blower level is further increased over that when the same as low and the rotational speed of the blower (10) is set higher.La présente invention a pour but de fournir un épurateur dair qui commande des augmentations de lélectricité consommée et du bruit et qui peut éliminer suffisamment de particules fines de lair. Pour atteindre ce but, linvention concerne un épurateur dair (1) qui est pourvu dun passage dair soufflé (8) reliant une entrée daspiration (3) pour aspirer de lair et des ouvertures dévacuation (4, 5) pour évacuer lair, dune soufflante (10) disposée à lintérieur du passage dair soufflé (8), dune unité de filtre (9) disposée dans le passage dair soufflé (8) pour recueillir la poussière dans lair et dun détecteur de poussière pour détecter la poussière dans lair, et qui fait varier la vitesse de rotation de la sou
