A photocatalyst device reducing the separation distance between a light source and a catalyst part while securing visible light illumination over the entire range of the catalyst part, reducing the package size, and increasing the amount of visible light irradiated to the catalyst part to enhance its photocatalytic reactivity.
The photocatalyst device, generating a photocatalytic reaction and emitting superoxide radicals into internal flow path of air conditioning case to purify air blown into a vehicle passenger room along the internal flow path, includes a photocatalyst body with a light source part and a catalyst part installed on it, where catalyst part causes a photocatalytic reaction by light emitted from the light source part, and a light processing part processing the light emitted from the light source part so as to increase an irradiance rate of the light of the light source part with respect to the catalyst part.