A hybrid vehicle drive system is designed to have dimensions that are shorter in an axial direction and improved centering accuracy of a rotor, in order to prevent deterioration of motor performance. A rotor support plate (15) has a flat-plate shaped disk portion (15b), and is fixed to a front cover (32) of a take off device (5), such as a torque converter, or the like, at the disk portion with a set block (67) and a bolt (69). A forward portion of the take off device is centered and supported by fitting a center piece (33) to a crankshaft (3). A support-plate hub (15a) is in contact with the center piece (33) at a small area (33c) in a vicinity of a fixing plane P of the disk portion (15b) and the set block (67), and thus centering of the rotor (13) is executed.