Security keys are typically needed to communicate with various network communication protocols of a mixed communication network. Thus, even if the difference in rotation of each wheel occurs due to the air pressure within each tire, the malfunction in which four-wheel driving is controlled based on the erroneous determination that the difference in rotation of each wheel is due to cornering or the state of the road surface can be prevented from occurring. 3) are disposed off-set outward in the radial direction, and the inner axial passages, when looked at in the radial direction, are disposed in the area of the rolling bodies and the outer axial passages cover at least a part of the front of the planet wheels.