A plurality of current sensors (41,42,51,52,61,62) are provided which are associated with a plurality of inverter circuits (40,50,60) that drive a plurality of motor generators (MG1,MG2,MGR), respectively. The zero adjustment of each current sensor is executed, during a nonconductive state that is identified by a halt of operation of the associated inverter circuit, if it is determined that noise affection is small due to the halt of operation of the other inverter circuits in the same casing (105). As a result, this can avoid a risk of performing a zero adjustment during a state in which the output of a current sensor exhibits no correct value corresponding to the zero current due to the noise affection by other inverter circuits. In this way, the zero adjustment of each current sensor for measuring a motor drive current can be implemented with high precision.