In recent years, "project-style art" which consists of appreciators' self-directed activities and the process of the activities has become popular. This is a kind of "participation-style art" in which the appreciator is indispensable. This paper focuses on the project-style art which has no definitive purpose at first, like the prosperity of a town, environmental protection etc., but has the reason of necessary expression style for an artist at the on-going process. For example, in the case of Hiroshi Fuji's work "Kaekko" as an operation system (OS), the building of relationships with appreciators, "education for art" and the roll of Fuji at the OS-expression are analyzed. As a result, I found that there are two close sides at the project-style art which are educational and contemporary-artistic.