To provide an actuator device for a flight control surface which can reduce a stress applied to the flight control surface when one of two actuators is operated. The present invention relates to a hydraulically-operated actuator device 30 which drives a flight control surface of an aircraft 1, including a first actuator 31A that is provided with a first piston rod 39A, and drives an aileron body 11; a second actuator 31B that is provided with a second piston rod 39B, and drives the aileron body 11 when the function of the first actuator 31A is lost or reduced; and a single second connection fitting 41 to which the first piston rod 39A and the second piston rod 39B are both connected, wherein the first actuator 31A and the second actuator 31B are connected to the aileron body 11 via the second connection fitting 41.