In the case where the rotation speeds of respective magneto alternating current (AC) generators of a plurality of power source apparatuses (10, 20, and 30) are approximately the same rotation speed and the total electric power generation demand is the same as or smaller than the maximum total generated electric power of the plurality of power source apparatuses (10, 20, and 30), the integrated control unit (6) for integrally controlling the plurality of power source apparatuses (10, 20, and 30) selects at least one of the plurality of the power source apparatuses (10, 20, and 30) and controls a voltage control unit (5) of the selected power source apparatus in such a way that the selected power source apparatus generates maximum generated electric power thereof, at the rotation speed, that is the same as or smaller than the total electric power generation demand.