In a three-wheeled vehicle provided with a power transmission mechanism for transmitting the output of an engine to left and right rear wheels via a continuously variable transmission, a gear box and inner shafts of drive shafts as left and right output shafts, the inner shafts which are output shafts of the gear box are provided apart in a longitudinal direction of the body. The overall length of the drive shafts can be increased. When the rear wheel is vertically moved, an angle of the bend of the drive shaft can be minimized. Further, the tread of the wheels can be reduced. Therefore, the width of the body can be reduced and the mobility of the vehicle can be enhanced. In addition, the gear case can be separate from the crankcase and attached to the crankcase with the differential mechanism being housed in the separate gear case.