With the use of data and AI, which are at the core of smart city functions, new governance models, such as privacy and AI ethics, are necessary in addition to compliance with personal information protection law. Simultaneously, embedding these governance systems in the design of services will increase their social acceptability. This study examines the ideal method of data utilization in smart cities based on the trends of the legal system with regard to personal information protection and privacy protection in Japan and overseas. It also presents research on the formulation of guidelines based on specific use cases. Additionally, the study provides an evaluation of the ideal method for the development of data rules in Japan and overseas, with regard to smart cities in general, and research toward the recommendations of the same.