So many students as 100 to 200 in one class are, in general, taking lectures at most private uni-versities in Japan. Effective education is not easy because of the existence of great difference of student's ability. There is a great issue specially what level the lecture should be focused on in a class. When the target sets at the middle level students, lower level students can not follow the lecture well, while the upper ones may feel tiresome. Author classified students into three levels as the upper, lower and major middle level students after the mid-term test, and let the higher level students teach low ability students one by one. As the result of this trial, not to mention for the low level students, higher level students expressed good efficacy for this education system.
