The world population is continually increasing, but the Japanese population is decreasing. By 2050, the Japanese population is calculated to be close to 100 million people,and by 2060, 40% of the Japanese are estimated to be aged 65 years or more. Data show an increase in the declining birth and aging rates of the population. The development of high-concentration urban structures willbeneededtosolvesuchproblems.However,adetailedvisionofthefutureisyet to be clarified and in the process of consideration. In this study, we developed an instrument called “Population Migration Tool,” which is based on plural planning and policy, after we formed afuture population distribution model. In addition, We also established a high-concentration urbanstructuremodelwiththistoolwiththeaimofconsideringthekindof urban structure local cities should target in the future.