The aim of this paper is to estimate the effects of inter-regional (prefectural) migration on the surplus, past surplus, future surplus and whole life surplus of prefectures based on 1995–2000 data in Japan. The surplus is the difference between income and consumption at the respective age, the past surplus at some age is the total of surpluses from the birth to the previous one of the age, the future surplus at some age is the total of surpluses from the age to the death age, and the whole life surplus at some age is the total of the past surplus and the future surplus. Here, the future surplus is discounted and the past surplus is amplified by the interest rate respectively. The future surplus is also discounted by the survival rate at respective age. Therefore the surpluses may be plus or minus.
According to estimation, per capita surpluses are different very much owing to the age and sex, and the inter-prefectural migration is also different with grate degree owing to the age. Then we are able to indicate that the inter-prefectural migration has the grate effects with plus or minus on surpluses of the region.