To provide a control device for a pressure-response operation type actuator to improve durability of a position sensor.

A control device for a pressure-response operation type actuator 5 is provided with a pressure chamber 5a to which a variable pressure is fed, and a moving partition wall 5b displaced in response to a pressure in a pressure chamber, and drives an object 5A to be driven through displacement of the moving partition wall 5b. In this case, the control device comprises a non-contact type position sensor 15 to detect the displacement position P of the moving partition wall 5b; various sensors 14 to detect the control states Re, TW, and θof the object to be driven; pressure sources 19 and 20 to feed a variable pressure to the pressure chamber 5a; a first opening closing means 17 to regulate the feed time of a variable pressure; a second opening closing means 21 to regulate a variable pressure into an atmosphere pressure: and an ECU 13A to control opening and closing of the first and second opening closing means 17 and 21 in response to the displacement position of the moving partition wall 5b and the control state of the object to be driven.