A process for producing a crystalline titanium oxide coating film useful as a photocatalyst, photo-electric converting element, etc. The process is suitable for industrial production and enables the crystalline titanium oxide to be formed in a large amount. A crystalline titanium oxide coating film is produced via the following steps (a-1) and (b): (a-1) a step in which titanium or a titanium alloy is heated under the conditions of any of the following (1) to (3) to thereby form a titanium nitride on the surface of the titanium or titanium alloy: (1) in a nitrogen and/or ammonia gas atmosphere in which an oxygen-trapping agent is present, (2) in an atmosphere filled with nitrogen and/or ammonia gas after the atmospheric gas has been removed by evacuation, and (3) in an atmosphere filled with nitrogen and/or ammonia gas after the atmospheric gas has been removed by evacuation, an oxygen-trapping agent being present in the atmosphere; and (b) a step in which the titanium or titanium alloy obtained in the step (a-1) is immersed in an electrolytic solution containing an inorganic acid and/or organic acid and a voltage is applied thereto to conduct anodizing.