A purification unit is provided with a light source which emits light, a purification plate which causes a photocatalysis reaction by irradiation with the light, and a reflection plate which has a curved surface configuration, and is configured to reflect the light emitted from the light source for guiding the reflected light to the purification plate. The layout of the light source and the curved surface configuration of the reflection plate are defined in such a manner that an intensity of the light to be applied to the purification plate is biased toward an upstream side of an air flow path in the purification unit.
