This paper analyzes the supply structure of condominiums in the Osaka Metropolitan Area, namely, the area within a radius of 30 kilometers of Osaka City Office (Fig. 1), by examining the relationship between floor space index (hereafter referred to as FSI) and unit price per m (hereafter referred to as UPPm²), based on data in “Condominium Sales All over Japan” issued by the Institute of Real Estate and Economics (Fudosan Keizai Kenkyujo).<br> The process and result of this study may be summarized as follows:<br> First, the author has focused attention on chronological change in areas where construction of condominiums took place in Osaka Metropolitan Area during 1976-1990 (Fig. 2). This figure shows that construction of condominiums has gravitated gradually to the areas (which we shall call by the names of their local governments-that is, cities or wards) where land prices were relatively low. Second, dividing the local authorities into several groups according to FSI deviation (Figs. 3 and 4), shows that FSIs are higher in the direction of Central Osaka, turning lower outwards (Fig. 4). Third, division and grouping by analyzing deviation of UPPm² (Figs. 3 and 5) shows that UPP m² is higher in Central Osaka and, plateaus around Osaka City and traditional upper-class residential areas, compared with the east and west ends of Osaka City and areas along the Keihan, Kintetsu and Nankai Lines. Fourth, through studying the relationship between FSI deviation and UPPm² deviation, we have developed the area division which is shown in Figs. 3 and 6. Figure 6 implies that the higher the rank, the more advantageous it becomes to construct condominiums. But it does not well explain some irregular area distributions of ranks in the region. Trying to explain the phenomenon, the author has used to the method of cluster analysis on the data in Fig. 3 (Figs. 3 and 7), and derived Fig. 8, which then can be modified into Fig. 9.<br> The area distribution of each group seems to imply that, in Osaka City Area, high-FSI/high-priced condominiums are concentrated in the central part of the city, followed by medium-FSI / medium-price types and medium-FSI / low-price types spreading gradually toward the outskirts, in a pattern like concentric circles. High-FSI / medium-price types and low-FSI / high-price types are seen around the city's core district and in the traditional upper-class residential area, respectively, more or less like islands in the concentric circles. Outside the circumference of a radius of 10 kilometers, distribution in concentric circles seems to be replaced by sectorial distribution, where low-FSI / high-price and low-FSI/medium-price types are seen along the Hankyu and Hanshin Lines, while low-FSI/low-price types are seen along the Keihan, Kintetsu and Nankai Lines. It therefore may be concluded that the supply of condominiums in Osaka Metropolitan Area presents a dual structure.