The purpose of this study is to understand the inter-firm competition and cooperation, especially its logics and norms. First, it was suggested that inter-firm competition and cooperation is possible with respect to function, product/business and market. Furthermore, structure of inter-firm competition and cooperation shows the types of competition-oriented and cooperation-oriented. Second, various theories were introduced to explain the logic of inter-firm competition and cooperation. They include social relation theory, transaction cost theory, industrial organization theory, and resource-based theory. However these theories are need to be compromised to explain the mechanism of inter-firm competition and cooperation completely. Third. it was suggested that structural and operational condition should be fulfilled to invoke and maintain the commitment and trust as norms of inter-firm competition and cooperation. By the way under the structure of competition-oriented inter-firm relations the structural condition must be kept because the operational condition is hard to maintain. In contrast, under the structure of cooperation oriented inter-firm relations the operation condition can be kept easily. Finally, the successful model of inter-firm competition and cooperation introduced in this study can be applied to other types of inter-firms relations such as manufacture-distributor relations and buyer-supplier relations.