Recently, it has been reported that the organic compounds such as dirt and odors can be decomposed by photocatalytic reaction of titanium oxide (TiO₂). In the daily use of lamps and luminaries, the accumulation of dirt often reduces a great amount of light output. We have developed a new type of fluorescent lamp coated with photocatalytic TiO₂ film to improve those problems on lighting. At first, we estimated the decomposition of cigarette dirt on the lamps coated with TiO₂ films. The loss rate of light output could be decreased to half by decomposition of dirt during operating. Furthermore, we investigated the change in concentration of acetaldehyde in sealed box during lighting. It was found that the lamp could deodorize the air in the box by decomposition. At the same time, UV radiation from the lamp were absorbed by TiO₂ films. Thus, it was found that the users could be provided with the comfortable environment by application of the photocatalytic reaction to the lighting systems.