In this study we aimed to find out the actual condition of classroom, especially the appropriate class size in Japanese school. Thus we conducted a nationwide questionnaire survey on the teachers who were in charge of classes of elementary school, junior high school and high school. Through this survey we reached the findings as follows; 1)there were a little difference in environmental evaluation among the grade which they were in charge of, 2)there were significant difference in environmental evaluation among different levels of area per student, 3)from the factor analysis, we found out 2 factors; spaciousness and stability, 4)in the teachers' free description, width of the classroom was most important factor both in their satisfaction and dissatisfaction, 5)we could show the figuring process about the appropriate class size.
