The annual increase of the population of Osaka city, the second biggest city in Japan, amounts to approximately 100, 000 persons for these seven years (Table 1). The writer has investigated the social increase of population of the city. The results are as follows.
1. The influx and the efflux population has been both decreasing since 1951.
2. As to the migration of population between the city and the other prelectures, the influx population outnumbers the efflux population except for the case of two prefectures, Tokyo and Kanagawa. The affected spheres of influx and efflux almost coincide with each otler (Fig. 1). The principal part of both spheres is made tip of the outlying prefectures and the eastern Shikoku. The isopleths showing the rate of population migrated between Osaka city and other prefectures form a set of concentric circles more or less extending towards the west with the city as their center (Fig. 2.). This contrasts with these spheres of Tokyo city which extend towards the eastern Japan.
3. The migration of population between the city and Osaka prefecture has been decreaseing in number (Table. 2). The number of influx is larger than that of effux, while the difference between them is getting smaller. The affected sphere of the migration of population is considered to form a circular area with the city as its center.
4. The population migrated within the city area is also becoming eiialler in number. If the influx and the efflux population into and from Osaka city is examined by ward, the areas of influx and efflux roughly coincide with each other, forming a circular area with the ward of Higashi-ku as its center (Fig. 4, 5, 6).
5. The seasonal fluctuation of the migration of population has In also revealed by utilizing the statistics by month. The migration attains to its maximum in spring and autumn, the minimum in summer and winter (Fig. 7). This seasonal fluctuation is different in type from the migration brought about by marriage and the migation took place in provincial towns.
