A photo catalytic filter is configured such that a plurality of plate-shaped members on which a photocatalyst is carried face each other with a gap therebetween, and the gaps form an air flow path. Each plate-shaped member has end surfaces respectively on an air entrance side and an air exit side of the gap. A UV irradiation unit faces the end surfaces on at least one of the air entrance side and the air exit side of the plate-shaped members, and is a predetermined distance away from those end surfaces. An air supply path for taking air from a lateral direction substantially parallel to the end surfaces, and supplying the air to the flow path, or an air discharge path for discharging the air exiting the flow path to a lateral direction substantially parallel to the end surfaces, is formed between the UV irradiation unit and the end surfaces of the plate-shaped members.
