In this study, we focus on migration from metropolitan to outside areas in Japan, and quantitatively examine the personal and regional determinants of this process. At the regional level, our results show that the determinants of migration differ depending upon whether migration occurs from smaller to larger cities or vice versa. In the case of migration from larger to smaller cities, the residential environment beyond the metropolitan area is more important than employment opportunities. At the personal level, we analyzed the differences among the determinants of migration, looking at migrants according to age categories and based on their motivations for migrating. The main factors encouraging migration comprised opportunities for employment, education, and marriage.