Information Technology that is featured by standard communication protocol like Lon Works, BACnet is very useful for managing building systems. Now we can collect much data quickly and easily and to analyze them in detail with this technology. Under the circumstances in that saving energy and reducing CO2 are required strongly, important thing is finding the effective information for building operation and control from collected data and the analysis of them. In our project, the floor integration controller that integrates the each building systems was proposed. It enables to cooperate between the partial building systems and to save energy of HVAC or lighting system with communications based on open network. We call this system ”cooperative control” and experimentally applied to our building located in Japan (Osaka) almost two years. As the result, 29% of energy saving on the total energy consumption compared to no cooperative control system are accomplished. We especially describe about one of the cooperative controls, ”blind cooperative control” which use positively daylight to reduce energy consumption of lighting. On the other hand, the energy consumption of HVAC increases. Therefore this controller has to minimize the total energy consumption of HVAC and Lighting power. This work was supported by NEDO (New Energy and Industrial Technology Development Organization in Japan).