PURPOSE: To set a drill correctly in the orthogonal state to the bored face in a boring device applied to the complex curved surface part of the skin or the like of an aircraft.

CONSTITUTION: A tape switch 2, a face right angle display lamp 7 and a drill guide 8 are fitted to a spacematic drill motor body 1. A pair of contactless sensors 3a, 3b are fitted to one end of a drill guide 8, and a movable tail pad 6 and a motor 5 are fitted to the other end of the drill guide 8. The signals of the contactless sensors 3a, 3b are inputted to a face right angle arithmetic unit 4, and the motor 5 is driven so that the difference between the signals of both sensors is zero. The movable tail pad 6 is thereby moved vertically to adjust the position of the drill guide 8. Since a drill is thus disposed orthogonally, a hole can be bored correctly in an aircraft skin 32 and an internal skeleton 33.