It is important for corporate alliances not only to make up for lack of resource but also to share knowledge among their members effectively. Based on previous studies by Nonaka (1990) and Matsuda (1990), we use the concept of “inter-organizational intelligence,”to analyze the knowledge sharing mechanism in an alliance community. Through case studies and the results of questionnaires, this paper shows that inter-organizational intelligence is different from organizational intelligences in terms of creating business planning skill, which is connected to the success of alliances, and that inter-organizational intelligence is formed through two steps.