DRIVING FORCE TRANSMISSION DEVICE

A driving force transmission apparatus 1 includes a tank 44 which reserves lubricating oil in an accommodating space 12a which is interposed between a housing 12 and an inner shaft 13 and an apparatus case 4 which has a cylindrical accommodating portion 40c which accommodates the housing 12, and in the case 4, the accommodating portion 40c has an inner circumferential surface 40b which faces an outer circumferential surface 19e of the housing 12, and the tank 44 has an oil inlet port 441 a which is opened to the inner circumferential surface 40b of the accommodating portion 40c and through which the lubricating oil in the accommodating space 12a is let in based on a centrifugal force generated in association with the rotation of the housing when a four-wheel drive vehicle travels forwards in a two-wheel drive mode.