Method and apparatus for cutting a pattern of a printed wiring board and for cleaning a printed wiring board wherein a laser beam is irradiated onto a printed wiring board to evaporate the irradiated portion. A suction nozzle for sweeping a surface region including the cut spot of the printed wiring board and for withdrawing molten matter adhering to the region, or a tape feeding apparatus by which an incombustible sheet or tape is disposed in close contact with the cutting spot of the pattern of the wiring board for collecting particles scattered during the pattern cutting is provided. Further, a laser beam is applied to a resin layer on an internal-layer pattern to expose the pattern, the width of the internal-layer pattern is determined, and the internal-layer pattern is cut in accordance with the determined width. Laser beams are applied to the printed wiring board obliquely from two directions to dry-clean the wiring board.