To certainly support a car weight by respective wheels at the time of traveling on a bad road having a large convex/concave portion, to prevent a lateral rolling and a front/rear rolling by applying a traction to the respective wheels and to cheaply realize this phenomenon.

Wheels 3 are suspended at four corners of a frame 2 of a four- wheel-drive AUTOMOBILE by a flat spring type suspension 4 and a car height adjusting device for varying a vertical space of the wheels 3 and the frame 2 is independently provided on the four wheels 3 respectively. The car height adjusting device is provided with a vertically expandable/shrinkable quadric rotation interlocking type shackle 20 for connecting a movable end side of the flat spring 6 and the frame 2 and an electromotive wire winch as a driving device for vertically expanding/shrinking the quadric rotation interlocking type shackle 20.