A hybrid vehicle power transmission device provided with a power distribution mechanism composed of a planetary gear device for distributing motive power of a drive source to a motor and an output shaft is further provided with a damper device in a power transmission path between the power distribution mechanism and a first motor. Consequently, the damper device receives only reaction torque dealt by the first motor through the power distribution mechanism with respect to drive torque of an engine. Thus, since the torque transmitted to the damper device is smaller than the drive torque of the engine, the torque capacity of the damper device can be decreased and the size of the damper device can be reduced. As a result, the overall size of the power transmission device can be similarly reduced.