The methodologies of the sociology and history of science have not yet well applied to the history of geography on the empirical level. A primary reason is that a rather superfi-cial acceptance of these methodologies results in oversimplified dichotomies in orientation, geography/society, and approach, internal/external, and that these dichotomies cause a lack of attention to the causal mechanism mediating the two poles. The attention on the me-diating agency, the community of geographers, is indispensable for understanding the history of geography, especially the history after its professionalization. The effect of the community of geographers on the cognitive aspect of geography has not been well studied except for Johnston (1983b)'s rather general characterization of the scientific community. As a step toward the examination of this effect, this paper treats the function of a learned society in insti-tutionalizing geography.<br> The concept “institutionalization” of a science is often regarded as equivalent to becom-ing an institution of society, namely “professionalization”. Following Whitley (1974), however, we should use it more comprehensively as “patterning of actions and meanings”. This sug-gests that institutionalization of a science consists of two aspects: social and cognitive. An important element common to both is an increasing mutual dependence between scientists. Establishment of a learned society is one of many ways to increase interdependence; the effect is more extensive than other strategies. And the establishment and sustainment of a learned society itself presupposes some degree of pre-existing institutionalization. The main functions of a learned society are, 1) externally, to demand recognition of the discipline from the outside, and 2) internally, to facilitate communication among scholars as well as to guide the future direction of the discipline by providing forums for communication.<br> This study limits itself only to the internal and social functions of a learned society, ignoring the relationship with the outside and the cognitive aspects of institutionalization. Generally two facts should not be overlooked in discussing the development of geographical societies : societies which were not necessarily academic were established at an early stage of institutionalization in an era of expansionism and nationalism; in this environment, geography was professionalized according to political intentions rather than the degree of its maturity as a science. In Japan, these factors were the main causes of discordance between those societies established before the professionalization and those based on the academic profession.<br> Geography departments had already been established at the two Imperial Universities, published in GRJ was rather low, while only a small number of the articles in GRJ were read at the conferences and meetings (Table 2). Thus these two kinds of forums were not structured hierarchically but juxtaposed functionally. This also indicates the partiality of the AJG's coverage regarding communication among geographers.<br> It can be concluded that the AJG in the prewar period had gathered scholars from a rather wide range as its members, not only nominal ones but also active ones, but that the AJG's incompleteness of membership coverage resulted in its failure to bring about the in-terdependence among geographers to a wide extent.