To make a hybrid vehicle travel without using a battery by balancing the amount of electric generation and the amount of power consumption by two motors in the hybrid vehicle.

An engine EG is feedback-controlled to a target engine speed NE* to stop the operation of the inverter P1 of an electric generator GN when a breakdown occurs. When the generator GN is rotated at a specified speed, back electromotive force is generated in each phase coil of the generator GN, and when a motor MG is connected to the generator GN as a load, electric current flows through a diode for protecting the inverter P1 for generating electricity. Since the power generated is consumed by the motor MG as it is, the amount of electric generation and the amount of power consumption is well balanced with each other. At this moment, the connection between inverters P1 and P2 and the battery BT is disconnected by a system main relay SMR.