PURPOSE: To drive micro engines or air turbines, etc., by stepping down a foot lever extending horizontally, adjust the number of revolutions according to degree of stepping down and reduce frictional resistance between the lever and a sole, when stepping down the lever, by way of covering the lever with a cover-roller which can freely turn around the lever.

CONSTITUTION: The foot controller comprises a foot lever 1 extending horizontally, a revolving arm 3, which operates when applying the foot lever from the right-angled direction against the extended direction of the foot lever 1, a volume adjustor 8 for regulating resistance corresponding to number of revolutions of the revolving arm 3. When the foot lever 1 is applied, it drives the dental instrument, and changes its number of revolutions in proportion to degree of stepping down. Further, the cover-roller 2 that can freely turn around the foot lever 1, can enhance its controllability.