To prevent increase of friction due to formation of a slide contact part of a bearing even if thrust force acts on rollers during transmission due to bearing errors of a first roller and a second roller.

Part of torque toward a right and a left rear wheel from an input shaft 12 is transmitted to a right and a left front wheel 7R, 7L through the first roller 31, the second roller 32 on a crankshaft eccentric shaft part 16a, a drive pin 36, and output shaft 15 in sequence. Transmission torque capacity is optionally controlled by controlling rotational position of the crankshaft 16 by a motor 35 and increasing and decreasing distance L1 between shafts of the rollers 31, 32. The thrust force gets to act on the second roller 32 due to bearing error during the transmission is born by a thrust support member 41. Consequently, the thrust force does not act on a roller bearing 24, and it can be avoided that the thrust force acts on the bearing 24 and that friction increases.