To efficiently remove a harmful substance in a gas by ensuring the surface area of a photocatalyst and uniformly irradiating the surface of the photocatalyst with light.
Two photocatalyst units 12, 12 each of which is formed by laminating a large number of plate-shaped photocatalysts 11 at a predetermined interval are arranged to be opposite to each other. Harmful gas is allowed to flow as shown by arrows A, B. Two tubular light sources 13, 13 are arranged between the photocatalyst units 12 so that the length directions of the them cross the plate-shaped photocatalysts 11 at a right angle. That is, the plate- shaped photocatalysts 11 are arranged horizontally while the tubular light sources 13, 13 are arranged vertically. The tubular light sources 13, 13 are arranged in parallel to the flow of harmful gas.
MIYATA TERUFUMI
KATO YASUYOSHI
