PURPOSE: To make a required space small and improve the layout performance by converting vertical motion of a right and a left wheel to the rotary motion of a pair of a left and a right rod, and increasing the speed of the rotary motion to slide a pair of pistons for generating a damping force.

CONSTITUTION: A front suspension device 1 restricts rolling by vertical motion of a left and a right front wheel 5 at inverse phases to each other by torsion resiliency deformation of a stabilizer bar, unillustrated, and a damping force by a roll damper device 10. In this case, the roll damper device 10 is provided with a pair of a left and a right L-letter connecting rods 13 connected with a type A arm, and a pair of speed increasing mechanisms 14 of a planetary gear type for increasing the speed of rotation of a rotary shaft part 13b of the connecting rod 13. A damping force generating mechanism 17 is also provided for generating a damping force by motion toward the shaft of a pair of a right and a left piston members 16 threaded with output shafts 15 of the speed increasing mechanism 14 respectively, and 31A, 32B and 31B, 32A separated by the piston members 16 are connected with each other by connecting passages 33, 34 respectively.