The aim of this article is to examine the works（ oil paintings） of the Barbizon School,which represents one of the 19th century’s French realisms in terms of art. It is also aimed to explore if these oil paintings will be reliable sources for the study of historical anthropology, where paintings had rarely been paid attention to. In 2014 I had a chance,thanks to Millet’s 200th birth anniversary, of watching much more paintings of the Barbizon School than before. This experience deserved, for I could gain several clues to understanding how painters had produced their works.Barbizon is a name of a hamlet, 60km south-east from Paris, adjoining the forest,called Fontainebleau, which had been attracting a lot of young ambitious artists since the early days of the 19th century. They did not confine their sketch activities to those withpencil or chalk. They did oil sketches as well. They depicted nature as it is, say, depicted what they saw without any modification to meet the contemporary artistic standard.The classical, traditional landscape paintings with mythological, biblical or heroic figures in them, ‘ neoclassicism ‘ academically called, did not interest them at all, although it was, at that time, only through this genre that a painter could attain honor and fame.Influenced by romanticism, quite opposite to neoclassicism, and thanks to a political change （the revolution 1830）, those who worked in Fontainebleau became well-known.The core members of the Barbizon School came from them. I have observed their paintings and considered if they had really depicted what they saw. Having discovered the similar patterns in landscape, favorite colors, repeated modifications, and a network of friendship, I came to a conclusion that it was not necessarily the case. I also understood that the publication of a textbook by Valencienne,which was widely read among young artists, played an important role for the Barbizon members to decide how to paint. The realistic paintings of the Barbizon School, still,would be useful materials to help historical anthropologists interpret the life and nature of the 19th century if they considered those findings.