PURPOSE: To improve drive feeling by installing a link mechanism in the space ranging from a chassis frame to rear wheels, thus setting link arms long and securing a sufficient stroke of a buffer.

CONSTITUTION: The front edge 21a of a swing arm 21 is pivotally supported onto a chassis frame 2 through a pivot shaft 22, and a driving shaft 24 for rear wheels 23 and 23 is supported by the rear edge 21b. A link mechanism 33 consisting of a front link arm 31 and a rear link arm 32 is installed between the frame 2 and the swing arm 21, and the rear wheels 23 and 23 are suspension-supported through a buffer 34 installed between the link mechanism 32 and the upper part of the frame 2. Since the link arms 31 and 32 are arranged on the center line in the lateral direction of a car, and buffer 34 is arranged on the center line similarly, a torsion does not act onto the link mechanism 33 and the buffer 34 when the rear wheels 23 and 23 swing vertically.