Abstract: The invention concerns a stabilising device (1) for two-wheeled vehicle (2) comprising two struts (3) for stabilising the vehicle laterally by being supported on the ground on either side thereof. The struts are articulated to a support frame (4) and are coupled to a motor mechanism, which actuates them between a support position on the ground stabilising the vehicle and a raised position, spaced away from the ground. Said motor mechanism is associated with control means connected to means indicating the vehicle speed, said control means activating the motor mechanism in a direction lowering the struts when the vehicle speed is less than a critical value below which it is hard or impossible to ensure the vehicle balance and in the lifting direction when the vehicle speed is higher than said critical value.