To provide a perforating device for preparing a dripping bag capable of facilitating preparation of a draining bag for collecting a wet article or dust by perforating holes in the bottom of ordinary plastic bags without holes.

Two plates are coupled so as to be openable and closable with a hinge by fixing several perforating needles, each of which is approximately 5 mm to 1 cm in length, on one plate in a pinholder form and making holes to receive the needles in the other plate.