The aim of this research is to identify and analyze Japan's interests in the first amendment protocol to the ASEAN – Japan Comprehensive Economic Partnership (AJCEP) agreement using the study of political economy and international diplomacy. Japan's need for natural resources cannot be met alone, therefore Japan needs cooperation with other countries that produce all resources, both natural resources, and cheap labor needed to meet their needs. This Japanese-owned motive invites questions. The method used in this research is a descriptive qualitative method with data collection through a literature study. The results of this study indicate that they have economic and political interests in AJCEP cooperation, but even though Japan is politically and economically superior, ASEAN and Japan continue to work together for Japan's security and politics between Japan and ASEAN.