To reduce the weight, number of part items and size of a dual mass flywheel arranged between an engine and an transmission.

The power transmission of a hybrid vehicle is provided with a motor generator MG, a damper 13 and a start clutch C comprising a wet type multiple disk clutch arranged in the series between the crankshaft 11 of an engine E and the main shafts 12 of a transmission T. The special first inertia mass and the special second inertia mass need not to be arranged by connecting the first inertia mass comprising a rotor 14 of the motor generator MG to the second inertia mass comprising the clutch case 28 of the start clutch C with the damper 13, and constituting a dual mass flywheel FW. Therefore, the vibration and the noise can be prevented while avoiding increase in the weight, the number of parts and the size.