To provide a suspension device capable of keeping effective stroke of a shock absorber to approximately constant and ensuring durability of a motor.

The suspension device is provided with an air suspension 12 and a shock absorber 22 and is also provided with connection members 24, 27 for connecting the shock absorber 22 to a car body frame and a lower arm 10; a turn buckle 29 in which a reverse thread is formed on boss parts 33, 34 formed at both ends, thread shafts 25, 28 are thread-engaged with the part, a base end of one thread shaft is connected to the connection members 24, 27 and a base end of the other thread shaft is connected to the shock absorber 22; an outer peripheral gear G1 formed on the boss part at one end of the turn buckle; a support member 31 extending from one connection member and mounted with the motor 35; a driving gear G2 mounted to the motor 35 and engaged with the outer peripheral gear G1; and a controller 19 for controlling the motor 35 for rotating/driving the turn buckle 29.