To drive a motor to start from a suspended state by a vehicle driver having an engine and a motor-generator without using a pole position sensor.

A vehicle driver has an engine 1, a motor-generator 20, an output shaft 40 through which those driving forces are outputted, and a clutch 35 by which they are coupled with and decoupled from each other. A controller has a start control means which, in order to drive the motor-generator 20 from a suspended state, couples the engine 1 and the motor-generator 20 with each other by the clutch 35, turns the motor-generator 20 by the engine 1, estimates the pole position of a rotor 22 by a voltage generated by the rotation of the motor-generator 20 and drives the motor-generator 20 in accordance with the estimated pole position.