The purpose of this paper is to suggest a new approach to explicate the relation between interaction and its setting, especially for classroom studies. First, we introduce H. Mehan's studies about classroom organization as a typical argument and a comprehensive policy about approach for ‘institutional settings’. Second, we outline how J. Heap sees the perspective of Mehan's studies as a defective one, and show that the arguments have a point in common with S. Hester & D. Francis' criticism of the comprehensive policy. Third, we show how Heap develops the perspective of Mehan, and suggest the development as a ‘new approach’ that overcomes these defects. Then, we can recognize the significance of the ‘new approach’ for explicating classroom.