The living body consists of proteins, carbohydrates and fats. The above components are unstable to the change of circumstances ; thus ; when they are buried under the ground for a long time, they are disintegrated by physical effects such as pressure, water etc. However, it was recently reported that the part of the components of living body, especially fat thought in small guantity, remained in a relative stable state for many milleniuns. In addition, turned out that the structure of the composition of the fatty acid and sterol is different according to their species. For example, the plants - rice, barley, bean - and the animals - (togs, cow, pig, fish - have different structure of fat. Residual fat analysis is a research in the chemical composition of fat vemained in archaeological evidences on the basis of chemical structural differences as mentioned here in above. This paper introduces the residual fat analysis of archaeological evidences practical in Japan.