A dustproofing film (10) for a waveguide (4) is disclosed which is characterized by having an adhesive agent (12) applied to a peripheral edge area thereof and having formed in the area surrounded by the peripheral edge area a region not covered at all with any adhering substance and consequently allowing the electromagnetic wave to pass. A method for the production of a dustproofing film (10) for a waveguide (4) is disclosed which is characterized by cutting a prescribed shape (15) from a double-faced adhesive tape (20), removing a peel paper (13a) from one surface of the adhesive tape (20), attaching the part of the adhesive tape remaining (14) after the removal of the prescribed shape (15) to a film (11) formed of synthetic resin thereby forming a sheet material having formed within the area of the adhesive tape remaining after the removal of the prescribed shape a region (15) covered with neither an adhesive agent or a peel paper and consequently allowing the electromagnetic wave to pass, and cutting a prescribed shape from the sheet material around the periphery of the region for passage of the electromagnetic wave thereby forming around the periphery of the region for passage of the electromagnetic wave a peripheral edge region (14) having a peel paper (13b) attached thereto through the medium of an adhesive agent (12).