A device for quickly advancing/retracting a biopsy tool (or other driven object) into position through a colonoscope or other such scope. The device includes a drive actuator, a transmission for coupling the actuator to a driven object (biopsy tool), an attachment assembly that couples the device to the endoscope, such as to a biopsy port on the endoscope, an electronic control unit, and a user interface. Preferably, the driver/biopsy tool coupling consists of a motor and a combination of gears and friction rollers.
