Sick house syndrome caused by volatile organic compound (VOC) in the room is a serious problem in Japan. A photocatalytic wall paper was developed which is a wall paper coated with a visible light type of photocatalyst. When irradiated by light, the photocatalyst generates strong oxidative potential and decomposes almost all organic substances to water, carbon dioxide, and others. As a result of our experiment using the photocatalytic wall paper, toluene and acetaldehyde were decomposed efficiently even under a fluorescent lamp, and the photocatalytic wall paper had also strong anti-bacterial effect under the fluorescent lamp.