This study is focuses on Interregional Payment Balances (IPB) in Japan as the measurement of “Doshusei”, the Japanese domestic political reform. Conclusions for regional economic policies are suggested in the following three areas. First: deficits in IPB are formed when the imports of a region are higher than the exports of that. Deficits in the IPB have been covered for a long time by the central government in Japan as the “gifts”, but today this scheme has become difficult and needs to be changed. Second: profits in regional economies are more often brought by the intra-regional expenditures than by the regional imports. This shows the orientation of the open market is not always profitable for the regional economy. Third: IPB depends on both the marginal propensity to consume and the marginal propensity to import in a regional economy. The former is related to net savings and the latter to net exports in the regional economy. These two curves hold the same equilibrium point and both curves are not fixed on the only one point but flexible. There are most of equilibrium points. Thinking such as point of view, it is possible to escape from simultaneous dilemma of interregional economic unbalance. This study is a model application from this theory to the regional economy “Doshusei”. JEL Classification: H62, H72, R12, R13, R58