To provide a drilling device capable of solving problems wherein a hole is deviated from a set position and holes drilled from a surface and a rear surface are deviated, when taking a means for drilling a printed wiring board being thick due to multi-layer lamination from the surface and the rear surface by half each.

A through hole drilled from the surface and the rear surface of the printed wiring board 6 by half each is imaged by a video camera 11 in which an XY position of a rotary shaft of a drill 1 and an XY position of an imaging optical axis are moved and controlled in the interlocking relationship so that an imaged image of the hole drilled correctly at a set position is at a predetermined position set on an imaged screen. By image processing such as image analysis of an imaging signal, signals related to proper or improper drilling such as deviation of the hole for the set position, deviation of holes on the surface and the rear surface by shape analysis of the holes, defect due to breakage of the drill, are detected and outputted to perform control related to interruption of drilling.