Abstract: In a machine with a longitudinal guide forming, at both sides, two working surfaces, onto which articles are arranged for sewing their upper edges, there is provided a wrinkling device in which two vertical presser feet, inner and outer, are moved vertically in an independent manner and in time relation with the motion of a needle, so that they make wrinkles on an edge of the articles, in alternate position with stitches. The needle, provided with a thread, cooperates with a rotary hook connected with a spool of stitching thread; the needle extends in an arc concentric to a shaft that moves the needle with oscillatory and translatory longitudinal to-and-fro motion.