A suspension device includes a clamp bracket, a tilting shaft, a swivel bracket, a steering shaft, a case, an electric motor, and a transmitter. The electric motor and the transmitter are held in the interior of the case. The electric motor produces power to rotate the steering shaft about a central axis of the steering shaft. The transmitter transmits power from the electric motor to the steering shaft side. The case is located on a placing portion provided on the swivel bracket, and removably attached to the swivel bracket.