The economical load distribution adjusting device 10 acquires an optimal hydroelectric output, optimal demand, and optimal power price from the supply-demand planning device 23, acquires the planned hydroelectric output planned by the water level planning devices 21, and acquires a planned demand planned by the charge control devices 22. The economical load distribution adjusting device 10 reduces the power price of the time at which the planned hydroelectric output exceeds the optimal output and makes the water level planning devices 21 replan the hydroelectric output, and raises the power price of the time at which the planned demand exceeds the optimal demand and makes the charge control devices 22 replan the amount of demand.