To provide such a photocatalyst sheet that the sheet can be used by sticking to a conventional device, apparatus, member or building material to purify air or water or to remove odors or contaminants of the environment, and thereby, the sheet can be easily processed after the production to give an effect to purify the environment such as to decompose odors.

A photocatalyst 3 is applied on the surface of a base body 2 and an adhesive is applied on the back surface of the base body 2. The obtd. sheet is stuck to a device, apparatus, member or building material so that it gives a function to decompose odors or the like and to purify the environment by producing active oxygen and OH radicals on the photocatalyst when the sheet is irradiated with light. The sheet hardly requires maintenance.