A hybrid drive unit for vehicles, in which a power distribution device is arranged in a power transmission route between an engine and a wheel, in which the power distribution device has a first to fourth rotary elements capable of rotating differentially with one another, in which a first motor generator is connected to the second rotary element and a wheel is connected to the fourth rotary element, and which is capable of steplessly controlling a speed change ratio of the first rotary element and the fourth rotary element of the power distribution device comprising: a second motor generator connected to the third rotary element of the power distribution device; a third motor generator connected to the wheel in a power transmittable manner; and an electric circuit for allowing exchange of electric power among individual motor generators.