Antifogging mirror or self-cleaning glass can be realized utilizing photoinduced hydrophilicity of titanium dioxide. Application fields of functional titanium dioxide coating,a is now expanding rapidly not only in applications for glass but also in applications for polymer, metal and ceramic materials. The high hydrophilic surface of TiO2 is interesting also on the standpoint of the basic photon related surface science of titanium dioxide. In order to understand the photoinduced hydrophilic conversion on titanium dioxide coating in details, it is inevitably necessary to understand the relationship between the photo reaction and the surface crystal structure. In this paper, photoinduced hydrophilic conversion was evaluated on the different crystal faces of rutile single crystal and also polycrystalline anatase titanium dioxide to clarify the dependence of the crystal structure on the photoinduced hydrophilic conversion.