The purpose of the study was to analyze the structural relationship among teacher’s self-leadership, teamwork, teaching effectiveness, and work effectiveness, using the structural equation model. The study model and the hypothesis were set to achieve this purpose and the Confirmatory Factor Analysis was made to diagnose the conformity. The results of the fit index showed =166.347, GFI=.962, CFI=.971, TLI=.960 and RMSEA=.059. On the basis of the data analyzed, the hypothesis was verified and the results were as follows: First, self-leadership showed a meaningful and positive correlation with the teaching and work effectiveness as well as teamwork. Second, teamwork showed a meaningful and positive correlation with the teaching effectiveness but didn't have a meaningful influence on the work effectiveness. Third, self-leadership with teamwork mediation didn't have a meaningful influence on the teaching and work effectiveness. As a result, the study confirmed that the teacher’s self-leadership played an important role in achieving teaching or work effectiveness while teamwork didn't affect teaching or work effectiveness as mediation. Therefore, various ways to strengthen self-leadership are investigated and teamwork, more demanded in teacher’s group activities, needs to be activated through teacher’s meetings or training courses.