Examples for application of cultural properties using Infrared Reflectography System as method of investigation on mural paintings and letters are given. This work is carried out according to asking of examination on inner layer paintings and letters in order to conserve the mural paintings discovered in the course of repairing ancient architectures. It is difficult to find the inner layer paintings and fine decorative line, but we can be observed by using Infrared Reflectography System and thus these results can be used as original rebuilding and drawings of mural paintings. Also building-repairing year, building participant though the investigation of letters written on the roof wood can be known.