To provide a high quality spun yarn by reducing the generation of long fluffs almost uniformly from the starting of winding to full package, a method for producing the same, and also a fluff-laying down tool capable of being easily attached to the ring fine spinning machines of different makers or kinds without changing its specification.

The fluff-laying down tool (9) attached to the downstream side of a front controller (6) of the ring fine spinning machine comprises a fluff-laying down part consisting of a swollen curved surface, an attaching part (3) of a hanging piece (4) positioned at the side of the fluff-laying part (2), and the hanging piece (4) attached to the attaching part and capable of engaging with the shaft of the front controller (6) and position-fixing in a steady state. The method for producing the spun yarn is provided by using the ring fine spinning machine attached with the fluff-laying down tool (9), traveling a fiber bundle along with the swollen curved surface of the fluff-laying down part (2) while transmitting the twists from a bobbin to the bundle discharged from a nipping point of the front roller (6) and leading it to a ring traveller by twisting to the tip end of the fluff.