The invention relates to a method for producing tubular bags made from plastic film or from composite film having a plastic layer on the bag content side, having a self-cutting plastic closure attached to the tubular bag, consisting of a spout part having a fastening flange, a cutting body, which is movably guided in the spout part, and a screw cover having means for activating the cutting body. The film material (5) is supplied from a supply roll to a bag manufacturing machine and the plastic closure is sealed onto the film material in a spout region of a tubular bag. According to the invention, the film material (5) is thinned on the inside of the bag in a ring-shaped region, which is intended for cutting by the cutting body, by means of a thermal embossing process. The plastic closure is then positioned and sealed onto the film material such that the cutting organ embedded in the spout part can become effective in the thinned, ring-shaped region upon use thereof.