A reduction-drive device has a first and a second reduction mechanism and distribution device. The first reduction mechanism has a planetary carrier, a planetary gear rotatably supported by the planetary carrier, an internal gear in mesh with the planetary gear and a sun gear. The first reduction mechanism is supported by the housing so as to reduce driving force of the electric motor. The second reduction mechanism is positioned between the electric motor and the first reduction mechanism so as to reduce an output of the first reduction mechanism. The differential device is supported by the housing so as to distribute the output of the second reduction mechanism to a wheel side.