A power transfer system is constituted under a simple construction (a worm gear, transfer rod integrally installed with a worm sector gear, and lower control arm), thereby improving the efficiency of the power transfer of the toe-angle controlling mechanism for vehicle wheels. The worm gear and worm sector gear are closed in a cover part of a housing, acquiring the durability and reliability of the toe-angle controlling mechanism for the vehicle wheels. The toe angle is prevented from being varied according to the exterior force transmitted from the vehicle wheel, by a unique characteristic (no inverse-transfer power) of the worm gear and worm sector gear, thus improving the vehicle stability.