Due to rapid growth of China's national power, ”China Threat” has become an important issue since late 20^th Century. It involves not only academic debates over power issue, but also China's diplomatic policy. This article, by examining academic and public opinions, discusses discourse of ”China Threat” in the post-World War II Japan. This essay argues that the ”China Threat” discourse in Japan had a unique development: in earlier stage it followed whatever discourse raised by the US in the context of the Cold War system, but in later stage Japan’s discourse originated from its direct engagement with China.