Japan’s New Security Bills became a controversial policy during the reign of Prime Minister Shinzo Abe. Abe administration claims that Japan's new security bills have positive goals both for inside and outside the country. Nevertheless, the South Korean government responded negatively the implementation of Japan's new security bills. This study will explain why the South Korean government responded negatively towards Japan's new security bills, using the concept of national interest and theory of foreign policy decision-making in order to obtain better understanding about the specific reason that prompted the policy. The preliminary results of the research show that the South Korean government responded negatively toward Japan's new security bills because they overshadowed deep trauma of the past Japanese imperialism, in addition to the South Korean government regards the implementation of Japan's new security bills will have implications on bilateral relations, that the condition is quite susceptible. South Korean domestic political conditions, economic conditions and military capabilities to territorial disputes between Japan and South Korea became the most significant reason why South Korea responded negatively Japan's New Security Bills.