A fluid supply system is provided for an active vehicle suspension system, for supplying fluid pressure for a hollow working cylinder via a pressure control valve for adjusting suspension characteristics of the vehicle in order to suppress vehicular attitude changes and to absorb road shock vibration, the system having a pressurized fluid source unit for circulating a pressurized fluid through a fluid circuit extending via the pressure control valve and the working cylinder. A first sensor is provided for monitoring a relative displacement between the body of the vehicle and a suspension member rotatably supporting a road wheel thereof, for producing a relative displacement magnitude indicative signal. A second sensor is provided for monitoring a lateral acceleration exerted on the vehicle body. A predicted fluid flow amount through said fluid circuit is derived on the basis of the relative displacement indicative signal to produce a predicted fluid flow amount indicative signal. A magnitude of lateral acceleration greater than or equal to a predetermined acceleration criterion is detected to produce an acceleration detection signal. The fluid supply amount from the pressurized fluid source unit is derived of the basis of the predicted fluid flow amount for controlling the pressurized fluid source unit in order to adjust the supply amount of fluid toward the derived fluid supply amount in response to the acceleration detection signal for increasing the supply amount.