A differential mechanism is arranged below an infinitely variable transmission and a reduction gear mechanism. Front fitting parts and rear fitting parts for fitting suspension arms to a vehicle frame are arranged to the front and rear of the deferential mechanism. Even though the left and right suspension arms swing up and down, or a transmission and a reduction gear mechanism attached on a vehicle frame swing left and right with respect to the suspension arms, there is no interference of the transmission and the reduction gear mechanism with the suspension arms due to a space at the front and the rear of a differential mechanism, so that the vehicle frame can swing left and right and it is also possible to easily constitute a vehicle having an independent suspension.