PURPOSE: To suppress three kinds of lateral vibrations of yawing, lower center rolling and upper center rolling which are generated on the car body of a long railroad train.

CONSTITUTION: An active suspension device for railroad train is constituted of pneumatic springs 20f and 20r for supporting a car body, oil dampers 22f and 22r for suppressing the lateral vibration, fluid actuators 23f and 23r, control valve for controlling the fluid actuators, left and right acceleration speed detection meters 24f and 24r, left and right relative shift detection meters 25f and 25r, and a multivariable digital controller for determining the control input supplied to the control valve, and three kinds of lateral vibrations of yawing, lower center rolling and upper center rolling which are generated on the car body are controlled in active manner.