A wheel-axle generator equipped with a rotor configured to rotate with rotation of a wheel and a stator arranged around the rotor. The rotor is fixed to a concave portion that opens toward a vehicle outside of a tire wheel of a wheel. An arm member that has one end attached to a wheel-axle housing or a steering knuckle), that extends so as to stride over a wheel, and that, on a side of an outer surface of the wheel, further extends parallel to the outer surface of the wheel up to a central portion of the wheel. The stator is annularly arranged so as to surround the rotor and is provided on the other end side of the arm member. This arrangement provides space for accommodating a generator without shortening a wheel axle etc. and attaching the generator easily.