To provide a drilling device and a jig which can improve working efficiency while working accuracy can be improved.

The drilling device 10 related to this invention is constituted by a drilling machine 16 machining an internal thread in a hole 14 of a wall surface 12 and a suspension means 18 suspending this drilling machine 16. The drilling machine 16 is suspended in a condition balanced with a counterweight 48 by a wire 42 of the suspension means 18, to make a position adjustable in the vertical direction. The drilling machine 16, moving a truck main unit 32 fixed by a stopper member 38, can adjust a position in the lateral direction. The drilling machine 16, adjusting the position, is fixed to the wall surface 12 by an electromagnet 20A of a magnet stand 20.