Kawaguchi and Lee (1992) showed theoretically that some spatial equilibrium models, which had been thought to have unique equilibrium solution respectively, have not unique but infinitely many equilibrium solutions respectively and that it is very important to carefully check the uniqueness of equilibrium solution. In this paper, we make a case study of the spatial equilibrium models analyzed by Sasaki (1969, 1970, 1973), and show the importance and correctness of the above theoretical conclusion. Sasaki (1969, 1973) made a spatial equilibrium analysis of Eastern Japan's whole milk (fluid or manufacturing milk) market, assuming that the market area considered in his analysis can be grouped into n (10 for fluid milk and 8 for manufacturing milk) regions which have constant supply function and linear demand function of whole milk respectively, and made some practical reasoning based on both his analysis and the assumption of uniqueness of equilibrium solution. But in Section Ⅱ of this paper, we show that the uniqueness of equilibrium solution does not hold for the case of fluid milk market in his analysis, and that therefore the conclusion of his analysis must be corrected. Sasaki (1970, 1973) also made a spatial equilibrium analysis of Eastern Japan's pork industry, assuming that the market area considered in his analysis can be grouped into 16 regions which have linear supply function and linear demand function of hogs respectively, and made some practical reasoning based on both his analysis and the conclusion that the uniqueness of equilibrium solution hold in his analysis. But in Section Ⅲ of this paper, we show that the uniqueness of equilibrium solution does not hold in his analysis, and that therefore the conclusion of his analysis must be corrected considerably. In Section Ⅳ, we summarize the conclusion of this paper, the subject of which is shown in Section Ⅰ.