POWER TRANSMISSION DEVICE

This power transmission device (1) has: a motor (2); a first planetary reduction gear (4) that is connected to the downstream side of the motor (2); a second planetary reduction gear (5) that is connected to the downstream side of the first planetary reduction gear (4); a differential device (6) that is connected to the downstream side of the second planetary reduction gear (5); drive shafts (8A, 8B) that are connected to the downstream side of a differential gear; and a differential gear case (60). The drive shaft (8B) is disposed so as to pass through the inner diameter side of a rotor core (21), the inner diameter side of a sun gear (41) of the first planetary reduction gear (4), and the inner diameter side of a sun gear (51) of the second planetary reduction gear (5). A cylindrical section (552), that is a portion of the differential gear case (60) and is positioned between the first planetary reduction gear (4) and the second planetary reduction gear (5) which are aligned in a rotating axis X direction, is supported on the inner circumferential side of an intermediate cover (14) by means of a bearing (B3).