IT Strategic Headquarters of the Japanese government compiled the Priority Policy Program 2007, in which “Establishment of the structure for every citizen to be able to manage and utilize his health information by himself” and “Foundation of the e-Post-Office box for the realization of the social security service in aspects of people” are declared. For this purpose, a health information system is considered that delivers healthcare data to the server, where the data is to be individually self.administered by the owner. A patient can register his data, and download or reference it from any medical institution or home when necessary. We made a prototype system to realize such a personal health data referring system based on the e. post.office box concept. The system is to be used in field trial experiment with the staffs and students of Tokyo Institute of Technology using their ID Card. This prototype system is expected to be available for the policy suggestion in the realization of the e-P.O.Box stated in the Priority Policy Program of the government.