Japan signed the Convention on Biological Diversity (CBD) in 1992, and ratified it in 1993. Since that time, the Japanese Governmenthas sought to include the consideration for, and the preservation of biodiversity in the domestic legislative process. Howeverthese efforts did not attain full realization until 2008, when under the increasing pressure and influence of domestic environmental movement, the Japanese Government established the Babic Act on Biodiversity (Act No. 58 of 2008). This paper will examine and summarize the localization process of the CBDthrough an analysis of three sectors of Japanese society: state actors (including local governments), societal actors (non-governmental movements andinterest groups, etc.), and private actors. The paper considers the interaction of these various sectors in the development of biodiversity policy and argues for the potential the "Environmentalization" of Japanese law, i.e. that the legislative and the regulatory process include as a background assumption that biodiversity is an objective of regulatory protection. This environmentalization had become an important component in Japan's self-perception as a "responsible power" in international environmental circles.