In a vehicle that includes an auxiliary transmission mechanism where a high-speed range and a low-speed range are switchable, a carrier of an auxiliary transmission mechanism is coupled to a motor-generator to allow power transmission. When switching from the high-speed range to the low-speed range, the motor-generator increases a rotational speed of the carrier such that a rotational speed of a low-speed range piece is synchronized with a rotational speed of an input shaft. When switching from the low-speed range to the high-speed range, the motor-generator increases a rotational speed of the carrier such that a rotational speed of an output shaft is synchronized with a rotational speed of the input shaft. This allows range switch with a reduced gear change shock even while the vehicle is running.