Caused by the transition of global economic structure, competition between companies is changing toward knowledge management and innovation. Especially at the field of quick-change product, the superiority of technology is always the key factor of competition. Today, R&D department is important in any company. However, the efficiency of R&D not only depends on the ability of technology development but also management. Therefore, the managerial competency of R&D manager also attracts more and more attention. This study focus on the relationship between the management competency of R&D manager and department performance to find out what managerial competency can do to benefit the department performance. In addition, this study also tries to figure out the influence of education background on management competency of R&D manager. Through real case investigation, in this study two significant results are found: 1. The leadership domain, technical domain and conceptual domain of management competency of R&D manager have significantly positive influence on R&D outcome, staff competence, cost and budget control, financial benefits and control of schedule and quality of R&D department performance. The human domain has significantly positive influence on R&D outcome, staff competence and financial benefits. However, the administrative domain has no significant influence on all factors of R&D department performance. 2. The education background has significant difference on administrative domain of management competency. The administrative competency of a manager whose education background is not the science and engineering is better than whose education background is the science and engineering. On the other hand, The education background has no significant difference on leadership domain, technical domain, conceptual domain and human domain.