In this paper, we propose the roles of "intermediary actors" between scientists and policy makers for effective knowledge transferring in science-policy process. We adapted the Quinn's competing value framework to classify their roles into eight types. That is, intermediary actors in science-policy process play roles as monitors, coordinators, directors, producers, innovators, brokers, facilitators and mentors. We developed a list of 40 functions with each role consisting of five functions. Based on several case examples setting intermediary actors playing one of the eight roles between scientists and policy makers, we found that the intermediary actors play not only the designated roles, but also other roles for knowledge transferring. In all cases, intermediary actors play most of facilitator and mentor functions. These functions make effective knowledge transferring, that is knowledge sharing among scientists and policy makers.