A hybrid drive device has multiple modes that can be switched between each other, where energy loss is suppressed in each mode to enhance energy efficiency, the energy loss being loss of energy due tofriction resistance inside the engine of a vehicle produced, for example, when the vehicle uses regenerative braking and the vehicle travels electrically, in which cases the vehicle does not requiredrive force of the engine. The hybrid drive device has an input member (I) connected to the engine (E), an output member (O) connected to wheels, a first rotating electric machine (MG1), a second rotating electric machine (MG2), and a differential gear device (PG) having at least four rotating elements. The second rotating electric machine (MG2) is connected to the output member (O). The input member (I), the output member (O), and the first rotating electric machine (MG1) are respectively connected to different rotating elements of the differential gear device (PG). The output member (O) is selectively connectable to either of those two rotating elements of the differential gear device (PG) to which the input member (I) or the first rotating electric machine (MG1) is not connected.