An apparatus for producing a spun yarn comprising drafting units, delivery rollers and spinning devices disposed between the front rollers of each drafting unit and the corresponding delivery rollers. The spinning device guides a sliver drafter by the drafting unit along a substantially straight line and blows air against the running sliver so that some of the component fibers in the circumference of the sliver are fluffed out and caused to wind around the fibers forming the core of the sliver, and the circumferential speed of the delivery rollers is set to be equal to or higher than that of the front rollers.