In Japan, corporate governance problems and social responsibility problems have emerged after the bubble economy collapsed in the 1990s. Since then, many Japanese companies have been interested in corporate social responsibility (CSR) as well as corporate governance. However, what relationship is there between corporate governance and CSR activity? How much should companies expend their resources to the activity? Still nobody give definitive answers to the problems. In order to explain the Japanese situation and clear up the theoretical relation between them, firstly, we will briefly describe the problems of corporate governance and CSR which have emerged in Japan. Secondly, we will explain how the corporate governance problems can be analyzed based on the agency theory. We will also give an account of the relationship between corporate governance and CSR and the value of the firm theoretically. Finally, based on the formal agency model, we will prove that there is not only fungibility but also complementarity between corporate governance and CSR.