The purpose of the present invention is to provide a power transmission device that can maintain a prescribed wheel base without loss of vehicle stability. The power transmission device comprises: an internal combustion engine 25 mounted in a vehicle; a drive-source-side shaft 2 to which power from the internal combustion engine 25 is output; a flywheel 30 disposed on the drive-source-side shaft 2; a speed changer 10 that has an input shaft and an output shaft and that can change the rotational rate of the input shaft and output the changed rotational rate from the output shaft; and a clutch C1, C2 that can releasably transmit power between the drive-source-side shaft 2 and the input shaft. The internal combustion engine 25 and the speed changer 10 are disposed in the same direction as the travel direction of the vehicle. A differential gear mechanism 101 and a drive shaft 201 that transmit power output from the speed changer 10 to left and right drive wheels RW are located between the flywheel 30 and the clutch C1, C2 so as to be perpendicular to the drive-source-side shaft 2. The drive shaft 201 is disposed above the central axis of rotation of the drive-source-side shaft 2.