We have been developing optical adhesives and resins suitable for optical communication field for many years. So far, we have developed many optical adhesives and resins, such as adhesives for optical path coupling, high refractive index resins with 1.6 or more and so on. With recent progress of optical application technology, various kinds of optical materials which enable flexible optical control in various fields have been needed. Especially, higher refractive index resins have been attracted particular attention because the performance of optical devices, such as diffraction gratings, imaging sensors, LEDs and so on can be improved. We have been studying to realize characteristics that are difficult to realize with only organic materials by combining with inorganic filler. By applying the method, we also have been studying to increase the refractive index of the resin. In this paper, we report to realize photo-curable high refractive index resin with refractive index of 1.7 or more which has good optical transparency for near IR and visible wavelengths by mixing resins and inorganic nanofillers. Because the resin is composed of UV curable resins and inorganic nanofillers, it is also easy to obtain thin films with good optical characteristics by spin-coating and UV curing process. The high refractive index resin of 1.7 or more will become a promising one in various optical fields because of its good optical characteristics and easy processability.