PURPOSE: To eliminate the need of adding a sensor to a cylinder by detecting a pressure state on the side of the cylinder near a controller side where a control valve is disposed.

CONSTITUTION: This controller is provided with a pressure detection means 21A for detecting the pressure state of the suction and discharge openings 7 and 8 of an actuator 3 at a position separated from the actuator 3, a pressure control means 9 for controlling the supply and discharge of a driving pressure to and from the pressure detection means 21A and the actuator 3 and an electrical control means 15 for detecting the operating state of the actuator 3 based on pressure detection signals from the pressure detection means 21A. Then, the pressure of the suction or/and discharge openings of the actuator 3, for instance, the cylinder or the like for driving an automatic machine 2 or the like being a device 1 to be controlled is detected at the position separated from the actuator 3 and the operation of the actuator 3 is confirmed based on the detected pressure state.