Regarding output suppression control of a plurality of dispersed power sources linked to a high-voltage-to-low-voltage transformer of a commercial power system, the partiality of the output suppression of a plurality of dispersed power sources is eliminated and, cost increase of the dispersed power sources is prevented. If a voltage at a power receiving point of a dispersed power source 1a exceeds the upper limit of a proper value, then a power conditioner 4 suppresses an output to a power receiving point to store a surplus power into a storage battery 8 and transmit an output suppression start signal to a management unit 9. The management unit 9 transmits an output suppression command signal to the other dispersed power sources 1b through 1e of which the voltage at the power receiving point is not exceeding the upper limit of the proper value to make the other dispersed power sources 1b through 1e to suppress their outputs and store surplus power into storage batteries 8. The plurality of dispersed power sources 1a through 1e can be thus made to impartially suppress the outputs, so that the capacity of the storage batteries 8 can be reduced.