In Japan, due to the high density of rain fall every year, the river disaster frequently occur, and counter measure and disaster damage prediction of quick and accurate information over a very wide area is required. In order to improve the safety of the river embankment, especially the old one, by evaluating and estimating the internal condition (i.e. soil density, water content, groundwater level, existence of crack, water leakage) of river embankment, the non-destructive testing by thermal infrared camera is studied.