A long-term predictor predicts long-term predicted power indicating temporal changes in consumed power of a customer using a long-term prediction model. A short-term predictor predicts short-term predicted power indicating temporal changes in the consumed power of the customer immediately after a current time, using a short-term prediction model, based on temporal changes in the consumed power of the customer immediately before the current time. A controller controls charging and discharging of a power storage apparatus at intervals based on the long-term predicted power and the short-term predicted power. The controller predicts temporal changes in charging power, discharging power, and charged electric energy of the power storage apparatus, and when the charged electric energy is predicted to reaches a lower limit due to discharging of the power storage apparatus, the controller charges power from the power network to the power storage apparatus in advance.