A single-strand yarn includes a plurality of intimately associated staple fibers made from N strands of multi-filaments by stretching and controlled breaking, and then spun by a spinning process, where N is a natural number. Within the single-strand yarn of a sampling length according to the invention, a ratio of the number of the staple fibers, whose length is equal to or greater than 60% of a setup fiber length to the total number of the staple fibers, is equal to or greater than 60%. The sampling length is equal to or less than 10 meters. The setup fiber length is equal to or larger than 65 mm. The dispersion of the weight distribution in the average length of the single-strand yarn according to the invention is equal to or less than 60%.