This study investigated that the effects of self- growth and social support at the workplace on work engagement by focusing on the mediating effects of self-growth. A survey was conducted with 254 Japanese employees. According to results of previous studies,the self -growth was expected to mediate the relationship between social support at the workplace and work engagement,in turn,work engagement was expected to be associated positively with performance and negatively with strain. Furthermore,it was anticipated that self-growth would meditate the relationship between social support at work place and strain. In this study,Structural Equation Modeling (SEM) indicated that through the self-growth,social support at the workplace was positively associated with work engagement and negatively associated with strain. Moreover,work engagement was positively associated with performance,whereas it was not associated with strain. These results suggest the importance of enhancing self-growth through the social support at the workplace to work actively with improved performance.