The measures for energy saving in buildings have been tried because particularly the role of building division is very important for implementing national greenhouse gas reduction targets and Green growth. However there are many problems due to lack of relevant personnel to do this work. Furthermore it is expected that certification services will be increased by revitalizing the Building Energy Rating System and expanding the target of certification. Therefore Government must prepare for the expansion of the Building Energy Rating System by training experts with effort to supply low-energy building. This expert survey results are that 72% of the respondents answer that expansion of the certification authority is needed to prepare for increase in the certification and 87% answer that training experts is needed. In this study, we suggest the basic data for the introduction of obligation and expanding certification by analyzing the operating system and legal system of the Building Energy Rating System. Additionally, the operating and legal system of the Building Energy Rating System which is appropriate for our country will need to be built based on practices in developed countries to present way to expand the target of certification.