TiO₂ has three crystal phases and each phase exhibits different properties. The applications for TiO₂ strongly depend on the crystal structure, morphology, and size of the particles. For instance, anatase TiO₂ powders consisting of particles with large surface areas are used as photocatalysts, which are advantageous for absorption of compounds included in the reaction system at low concentrations. In contrast to the case of anatase TiO₂ photocatalysts, oxidation of water, which is difficult to oxidize, proceeds efficiently on large rutile TiO₂ particles. Anatase TiO₂ photocatalysts don’t have photocatalytic activity for oxidation of water. Size, shape, and phase structure controlled synthesis of TiO₂ nanocrystallites has long been one of the main themes in TiO₂ research. Main synthetic techniques have been utilized in the preparation of TiO₂ nanocrystals, among which hydrothermal treatment has been drawing much attention considering that it directly produces well-crystallized nanocrystallities of a wide range of compositions within a short period of reaction time. In this study, we carried out hydrothermal growth of rutile TiO₂ rods by using aqueous titanium trichloride (TiCl₃) solutions containing NaCl and PVP. Under the condition, a rutile uniform ultrafine TiO₂ particle was obtained, on which developed crystal faces were observed by a transmission electron microscopy (TEM) and scanning electron microscope (SEM). The obtained rutile fine particles showed high activity for degradation of 2-propanol and acetaldehyde under UV irradiation. These results suggested that the crystal faces help the separation of electrons and holes. The high activity and controlled crystallization of rutile TiO₂ will be discussed.