Urban Sociology in Japan is heavily influenced by Urban Sociology of America. In Japan, Urban Sociology has become a very important field of study. However, if it is said, today it is facing, in a sense, a deep crisis. This paper attempts at-explaining the present crisis of Urban Sociology in Japan as a result of infiltrations of certain unique characteristics of American Urban Sociology into the Urban Sociology of Japan : i) American society and its sociological thought ; ii) American cities and the characteristics of urban sociology ; and iii) The European reaction to American sociology and American reflection to it. Concluding from the above discussion, the natural scientific, empirical, pragmatic, positivistic characteristic of American Urban Sociology has placed importance on primary research at down-to-earth conditions of American cities. The main problem of Japanese Urban Sociology lies in the fact that it imported in an unprecedented speed the American Urban Sociology without giving due attention to the social thought lying behind it.