To reduce output loss, reduction in fuel consumption, reduction in durability, wear-out, noises and vibration of an engine in driving in the two- wheel drive mode.

This system includes a motor, a front differential gear 5, left and right front wheels 11 and 13, a driving force interrupting mechanism 15, a rear differential gear 23, rear wheels 29 and 31, a differential gear case 35, and a driving force interrupting mechanism 77. The motor is disposed at a front portion of the vehicle. The front differential gear 5 distributes driving force of the motor inputted into the differential gear case 35 to the left and right front wheels 11 and 13. The rear differential gear 23 distributes rotation of the differential gear case 35 inputted through a power transmission system to the rear wheels 29 and 31. The driving force interrupting mechanism 15 is disposed between the differential gear case 35 and the power transmission system. The driving force interrupting mechanism 77 is disposed between the power transmission system and the rear wheel 29 and 31.