To remove the odor of a filter and also to collect dust by installing a blast fan, a particle removing filter, a light transmissive filter, in which an adsorbent and a photocatalyst are exist, and a light source exciting the photocatalyst, and arranging a light reflective plate at both sides of an air passing surface of the light transmissive filter.

Air is taken in from an air intake 7 by the blast fan 5, and the dust is sufficiently removed by a prefilter 8 and a high efficiency particles removing filter 6, then the air is guided to a honeycomb filter 2. Zeolite and titanium oxide are deposited on the honeycomb filter 2, odor components are decomposed oxidatively while being adsorbed. At this time, since the both sides of the titanium oxide are excited with near ultraviolet rays emitted by the light source 4 and subjected to multi-reflection by two sheets of reflective plates 3, the odor components are oxidatively decomposed uniformly over the entire area of the honeycomb filter 2 and the odor components are completely removed. The air purified in this way is discharged from an air blow-off port.