This office building is the latest energy-saving building in Tokyo. By relocating ICT equipment outside the office to the data center in the building and replacing all desktop PCs with a thin client terminal, we have reduced the outlet and cooling loads in the office. Moreover, we control levels of air-conditioning and lighting using positional information of workers, which is determined in real time by smart phones and beacons. Using these technologies, we have reduced energy consumption per floor area by 60% compared to average office buildings in Japan.