To provide a photocatalyst carrier capable of decomposing a harmful organic substance, and the like, in a room or else and making the same harmless in the maintenance-free state over a long period.

This photocatalyst carrier is provided with fibers 2 which have light transmissivity and are provided with a plurality of fine pores 3 on the surfaces and a photocatalyst 4 consisting of titanium oxide, or the like, deposited on the surfaces of the fibers 2 with such a thickness as not to fill up the fine pores 3. The photocatalyst carrier is used for a filter, or the like, for air cleaner, or the like, and when the air cleaner, or the like, is installed on a prescribed location in a room or else, the harmful organic substance, and the like, in the room or else is brought into contact with the fibers 2 and are adsorbed on the surface of the fibers 2 and the inside of every fine pores 3. The harmful organic substance, and the like, adsorbed on the fibers 2 are decomposed into water and carbon dioxide and are made harmless because the photocatalyst 4 functions as a photocatalyst by allowing the fibers 2 to transmit light. The harmful organic substance, and the like, are not accumulated in every fine pores 3 and, therefore, the organic substance, and the like, can be decomposed in the maintenance-free state over a long period.