Abstract: When vibrations having a period at which pitching tends to occur in a vehicle body is detected, if its amplitude falls out of the range between "H" and "L", a control unit increases the damping force of each suspension unit by using an actuator. In addition, if the amplitude falls out of the range between "HH" and "LL", the control unit supplies a predetermined amount of air to each air spring chamber in response to an upward displacement of vehicle height, and exhausts a predetermined amount of air from each air spring chamber in response to a downward displacement of vehicle height.

Abstract: If a deceleration exeeds first set value G1 within set time T1 after the brake is depressed, a set amount of fluid is supplied to the fluid spring chamber of each front-wheel suspension unit. If a deceleration exceeds the second set value G2 when set time T1 or more has elapsed upon this operation, a set amount of fluid is exhausted from the fluid spring chamber of each rearwheel suspension unit. With this operation, since braking action for gradually increasing a deceleration is controlled by two stages, uncomfortableness which passangers feel in anti-nose-dive control can be greatly reduced. In addition, control is not performed only by depressing the brake pedal if an acutal deceleration is smaller than first set value G1.