Recently, it became an attractive topic to make a prior assessment for the education policies. We propose an agent-based modeling in order to evaluate an educational policy, which is to determine the number of teachers necessary in educational system. The proposed model focuses on improvements in the academic achievements of each individual as well as an age-group as a whole. As a result of this study, major findings are, 1) the effective strategy for the below-average students is to raise the ratio of teachers placed in the compulsory education; and 2) the effective strategy for excellent students is to reduce the ratio of teachers placed in the primary education.