To provide a device that can change an established pneumatic cylinder into a pneumatic cylinder attached with air quantity control device by any user, who does not have knowledge of pneumatic cylinders.

This device is installed with a three port-poppet type-solenoid valve (9), a pneumatic-electrical switch (6), a detecting switch for speed switching points (10), an exhaust throttle valve (11), a control apparatus (7) to the established pneumatic cylinder and circuit in order to achieve the object.