PURPOSE: To solve insufficiency of lubricating oil in a control mechanism by providing a lubricating oil introducing path for introducing lubricating oil to the control mechanism in a position distant from a power dividing mechanism and a lubricating oil dam for accumulating the introduced lubricating oil to ensure its level.

CONSTITUTION: When lubricating oil in a differential gear housing 4 is scrape up-stirred especially by a ring gear of a differential gear mechanism, fluidized scattering lubricating oil is introduced to a control mechanism 7 in a position distant from the differential gear mechanism via a lubricating oil introducing path 8 as shown by a void arrow mark, and further the introduced lubricating oil from the lubricating oil introducing path 8 is accumulated by a lubricating oil dam 9 to ensure a level of oil enough for partly immersing a washer ring 33, needle bearing 34 and a slider ring 35 of the control mechanism 7. Accordingly, generation of shortage of the lubricating oil is prevented by storage of the lubricating oil even when a lubricating oil introducing amount via the lubricating oil introducing path 8 becomes short, for instance, due to a low speed, low oil temperature, etc.