The purpose of this study is to review existing studies on knowledge brokers and communities of practice in order to construct a new concept of knowledge brokers for future study. Previous studies have shown that communities of practice are informally constituted and create knowledge organizations through mutual engagement among the members of companies. The multi-membership of knowledge brokers allows them to play important roles in knowledge organizations. The major findings of this study are as follows. (1) The multi-membership is composed of two factors, "acceptance of diverse opinions" and "knot-working". (2) "Acceptance of diverse opinions" and "knot-working", as factors of the multi-membership, have a direct effect on "integration of diverse opinions". (3)"Integration of diverse opinions" has a direct effect on "the role of knowledge brokers". The proposed theoretical framework has implications for future studies on knowledge brokers, as well as on knowledge transfer research.