The purpose of this study was to examine the mediating effect of social support in the influence of education institution employees self-differentiation upon active stress coping strategy. Summarizing the results of this study, they are as follows. In consequence of analyzing multiple regression analysis on education institution employees self-differentiation, active stress coping strategy and social support, a social support partially mediated the relationship between education institution employees self-differentiation and active stress coping strategy. This study confirmed correlation among education institution employees self-differentiation, active stress coping strategy and social support and clarified that a social support, which is an individual s environmental factor, has partial mediation. A social support can be known to be a psychologically․emotionally important factor in understanding education institution employees active stress coping strategy. These results can help relieve stress through an active response, which is an efficient way to cope with stress in the workplace. This could help develop the stress mediation program.