The purpose of this study is to clarify the global citizenship education in Japan by examining educational practices in collaboration with Sustainable Development Goals(SDGs) conducted in Japan. Therefore, we considered the practice of the curriculum and SDGs as a case study in Japan's first national public International Baccalaureate(IB)-accredited elementary school, and examined how to foster global citizenship. The case school developed and managed a curriculum that introduces Primary Years Programme(PYP) based on the national curriculum guidelines. In particular, it was attempting to cultivate global citizenship by establishing and operating the subject “Inquiry” that integrates Social Studies, Science, Living Environment Studies, and the Period for Integrated Studies. As a result of examining the class practice in connection with SDGs from the aspect of global citizenship, the following characteristics were revealed. First, it was structured so that students could broaden their perspective horizons from the surroundings of the child to the global scale. The class was designed and practiced so that children could practice and act on the SDGs with a sense of ownership. The children approached problem-solving by critically recognizing through discussions about resource awareness and the practicability of solutions. The cases examined in this study provide meaningful implications for the field of school education in Korea, where interest in IB is gradually increasing.