PURPOSE: To increase the lifting stroke of a wheel while maintaining the rigidity of camber of the wheel by arranging respective upper and lower ball joints so that the ball studs can be fixed to respective control arms while respective balls are turned upward or downward respectively.

CONSTITUTION: Upper and lower arms 2a, 2b (not shown) of a knuckle 2 for journaling a wheel 1 are connected to the ends of respective upper and lower control arms 3, 4 which are supported by a vehicle body so as to be oscillatable in the up-and-down directions, via respective upper and lower ball joints 5, 6. In the abover constitution, the upper ball joint 5 is arranged so that the ball stud 5d is fixed to the upper control arm 3 while the ball 5b being internally installed in the upper arm 2a of the knuckle 2 is turned upward. And the lower ball joint 6 is arranged so that the ball stud 6d is fixed to the lower control arm 4 while the ball 6b being internally installed in the lower arm 21 of the knuckle 2 is turned downward.