It has been demanded to produce titanium dioxide having an excellent photocatalytic activity and an excellent super-hydrophilic property by a simple procedure suitable for the production on an industrial scale. Rutile-type titanium dioxide having an excellent photocatalytic activity can be produced by carrying out the anodic oxidization of the surface of a base material comprising titanium or a titanium alloy by applying a voltage (e.g., a high voltage) or carrying out the anodic oxidation of the surface of the base material under high current density conditions. Further, a film is produced on the surface of the base material by the anodic oxidation technique by applying a voltage or the anodic oxidization technique under high current density conditions, and the film is subjected to heat treatment, thereby producing rutile-type titanium dioxide having excellent crystallinity.
