Energy demand in an entire community including multiple demanders is properly predicted and energy consumption thereof is properly controlled. Every day, some demanders are selected from the community and a request to adjust energy consumption for the following day is sent to the selected demanders. To decide a content of the request, energy demand for the following day is predicted. In this case, demanders which did not receive a request on past days are specified, and demand in the community for the following day is predicted based on the actual energy consumption by those demanders on the past days.