To improve the high abrasion, high antifouling and high water resistances and persistence of hydrophilic actions in the dark.

This hydrophilic thin film is obtained by laminating a top layer composed of a metallic compound thin film onto a photocatalyst layer composed of a titanium dioxide thin film or a thin film mixed with the titanium dioxide and a metallic compound. As a result, the abrasion, fouling and water resistances are improved by the top layer composed of the metallic compound thin film. Since the metallic compound mixed with the titanium oxide or the metallic compound in the top layer is a luminous substance, hydrophilic actions are maintained for a long period even without being exposed to light. The hydrophilic actions in the dark are maintained for a long period even if the photocatalyst layer is especially composed of only the titanium dioxide thin film.