To obtain a photocatalyst which can use a good catalytic capacity without deteriorating a base material constituent when mixed into the constituent by a method in which the release of hydroxyl free radical is controlled by coating a photo-semiconducting substance with a porous substance, and a function to release hydrogen peroxide outside the coating layer is demonstrated.

In this photocatalyst which is used for the decomposition and removal of environmental pollutants in water and air, a photo-semiconducting substance is coated with a porous substance, and has a function to release hydrogen peroxide outside the coating layer. As a form to coat with the porous substance, for example, a porous microcapsule containing the photo- semiconducting substance, etc., are named. Preferably, a conductive substance which is brought into contact with the photo-semiconducting substance is made to exist, and titanium dioxide is used preferably as the photo-semiconducting substance. The photocatalyst body is used as an article having an antibacterial function in which part of the photocatalyst is fixed while being exposed to the surface.