An apparatus for actuating a valve. The apparatus comprises: an actuator device comprising a piston contained in a cylinder; the actuator device being actuated by a pressurized fluid, in particular compressed air; an opening/closing mechanism of a valve actuated by the actuator device; and a valve device to control and check the flow of pressurized fluid from and toward the actuator device in order to open/close the valve. The valve device is fixed to a front face of the actuator device on the side of the opening/closing mechanism of the valve.