After a collision has been detected, all the upper arm transistors of inverters (41, 42) are turned off, and all the lower arm transistors of the inverters are turned on. Then, when no counter electromotive force is generated in any one of motors (MG1, MG2), a gate voltage (V2) lower than a gate voltage (V1) at which each upper arm transistor completely turns on is applied to at least any one of the upper arm transistors of the inverters (41, 42), and at least any one of the lower arm transistors of the inverters (41, 42), which is serially connected to the at least any one of the upper arm transistors to which the gate voltage (V2) is applied, is turned on.