"This study was designed to examine the relations among optimism, emotional regulation style, and psychological well-being. The data in this study were collected from 340 primary school teachers in Busan with Optimism, motional regulation style and Psychological well-being scale each. T-test, one-way ANOVA, simple and multiple regression analysis were applied to data processing. The results of this research were summarized as follows : First, Optimism, emotional regulation style, and psychological well-being had not statistically significant differences in demographic factors(gender, age, working experience) of primary school teachers. Second, Optimism and psychological well-being, emotional regulation style and optimism showed a positive correlation. Active style had statistically significant influence. Third, Optimism had positive effect on psychological well-being. The more optimism and active and avoidance style (the subtype of emotional regulation style) were combined strongly, the better psychological well-being could be predicted. On the basis of the study results above, teachers' psychological well-being and the quality of teachers would be improved if teachers' optimism was advanced, the plan for problem-solving was set, the active emotional regulation style was used and the use of avoidance style was limited. As a result, when teachers' influence on students was considered, their optimism formed by interpretation style, linguistic habits and behaviors, active emotional regulation style for relieving negative emotion and psychological well-being are essential factors for health school life and their life to both teachers and students. Based on the findings, limitations of the current study and the suggestions for further research were offered. Keyword : Primary School Teachers, Optimism, Emotional Regulation, Psychological Well-Being"