Since 1980, regional decentralization has become a global trend. In Japan, cross-boundary cooperation is known as ”Regional Cooperative Administration,” which is centered on regional decentralization. In order to establish an efficient local government that is capable of subsuming further authority from decentralization, Japanese government progressively advocates the reform of administration by upholding the principles of Regional Cooperative Administration. The three principles of Regional Cooperative Administration are: 1. Delineating the Regional cooperative administration boundaries and conducting living zones designs. 2. Promoting municipal mergers. 3. Establishing joint management of regional administrations. By establishing a system of cross-boundary cooperation, we would not only be able to more efficiently allocated national resources to advance financial situations of regional governments, but also be able to better carry out the ideal of regional decentralization.