An electric power system includes a plurality of combinations of one of electric loads, which transmit/receive electric power, and one of power converters which is connected to the one of the electric loads and performs power conversion operation according to a predetermined switching synchronization signal so that electric power is transmitted/received to/from the electric load, the combinations being connected to a predetermined intermediate point so as to be parallel to each other, and a power conversion control unit which controls operations of the power converters. The power conversion control unit variably sets switching phases of the power converters depending on operating conditions of the power converters.