The idea of "social distance" is often used as a concept for the empirical research of social relations in American sociology. Georg Simmel, a German sociologist, adopted the idea of "distance" to describe one aspect of social interaction, that is, the discrepancy between spatial and "social" distance. Robert E. Park noticed its analytical importance and suggested the application of the idea to "the Race Relations Survey in Pacific Coast" (1923-). Emory S. Bogardus modified it far more, and invented "social distance scale" to measure the intimacy in racial relations, especially American citizens and Oriental immigrants.<br> For Park and Bogardus, "social distance" had an important role in their research method because it compensated for the deficiencies in their main method, "life history". But they omitted some implications suggested in Simmel's motif. On the one hand, Park and Bogardus did not acknowledge the analytical importance of "spatial distance" in social relations. They paid much attention to the spatial "nearness", but could not find the meaning of spatial "remoteness" in social interaction. On the other, they treated the attitude of maintaining "social distance" too negatively. As Simmel and Goffman mentioned, the maintenance of "social distance", like etiquettes, is often indispensable in urban life.<br> Park and his colleagues discovered the great efficiencies of "social distance" as a research method. However, they lost a chance to consider these aspects of social interaction because of their bias to "social distance".