PURPOSE: To convert alignment of a suspension device to its best condition with simple arrangement so as to make it possible to steer rear wheels, by driving driving means in response to rear wheel steering signals so that it deforms the suspension device supporting portion of a subframe.

CONSTITUTION: A rear suspension device A consists of a wheel support 2, an A type upper arm 3, a lower arm 4 and a shock absorber 5 and is supported on the body of a vehicle via a subframe 7. In this case, the subframe 7 comprises a horizontal portion 71, first diagonal portions 72 each extending diagonally downwardly from one end of the horizontal portion, and second diagonal portions 73 each extending diagonally upwardly from the lower end of each of the first diagonal portions, the top 73a of each of the second diagonal portions 73 having one end of an oscillating arm 9 pivotally mounted thereto. The center of the oscillating arm 9 is moveably supported by a bracket 10 provided at the center of the lower face of the horizontal portion 71 of the subframe 7. A power cylinder 12 is mounted on the lower face of the horizontal portion 71 and the end of the output shaft 14 of the power cylinder 12 is connected to the middle portion of the oscillating arm 9.