Since World War II, Japan has undergone rapid metropolitanization, characterized by concentration of population and central functions, and increased accessibility. The modern urban system is represented by three major metropolitan areas, the Shutoken (Tokyo), Chukyoken and Keihanshin. The present paper takes a central place theoretical approach to analyse the Keihanshin Metropolitan Area, comprising the three main cities of Osaka, Kyoto and Kobe.The major objectives of the paper are as follows:1) to identify one and two dimensional changes in population and in retail activity, and2) to analyse the evolution of centrality and the process of centrality change.The results are as follows:1) An analysis of the population and retail indices shows a state of balance for both, although the degree of equilibration is greater in the retail index than in the population index. That is, the relative proportions of population and of retail activity in the three cities of Osaka, Kyoto and Kobe are declining.2) Analysing the population and retail indices according to two dimensional changes, both centers of gravity (Xcg, Ycg) are situated in the north side of Osaka. However, the center of gravity moves irregularly, reflecting the complex changes occurring within the metropolitan area. By calculating the standard distance (Sd), it is shown that the population index tends to exhibit inner sudstantiality, while the retail index displays outer dispersion. Equiprobability circles between the population and retail indices do not differ in recent years, and indication of equilibration in space.3) A calculation of centrality shows that, generally, the mean (X) of centrality (L.Q.) is rising, and the coefficient value of variance (σ/X) is decreasing. Therefore, there is not a major qualitative difference among cities, towns and villages. The proportion of cities, towns and villages with a high value of centrality has risen to 85.8%, and this rise indicates the process of equilibration of the population and retail indices.4) Among cities, towns and villages whose value of centrality is over 1.0 are the core cities of Osaka, Kyoto and Kobe, the local centers (such as Himeji, Wakayama, etc.) located at the periphery of the metropolitan area, and some others not influenced by the metropolis.5) Among cities, towns and villages on the outskirts of the three major cities, there are almost none with a value of centrality of over 1.0, and these places are generally thought to be dependent upon the core areas. However, these places exhibit rising population and retail indices, as well as increasing values of centrality, an indication that growth and development are occurring.In conclusion, it can be said that the Keihanshin Metropolitan Area is moving toward equilibration, and that this trend is shown by positive changes in the population and retail indices, and by general increases in the value of centrality. This means that there is no clear difference among high order and low order cities, towns and villages. On the contrary, the population and retail indices for the core areas of Osaka, Kyoto and Kobe are declining, while those of peripheral cities, towns and villages are rising remarkably. This is an example of a large scale “doughnut” phenomenon. However, the core cities of Osaka, Kyoto and Kobe maintain high degrees of centrality, and there are very few values of over 1.0 on their outskirts. Therefore, although population and retail activities have become almost completely dispersed, the main cities are still functioning as metropolitan cores. At the same time, the cities located at the periphery of the metropolitan area are gradually increasing their values of centrality, and this trend indicates that the primate metropolis structure is changing.