One embodiment of the present invention relates to a spool for a fly reel, which is rotatably attached to a frame (110) mounted on a fishing rod to wind a fishing line, and which comprises: a rotation frame (120) rotatably coupled to the frame (110)； a winding drum (150) which has a locking protrusion (152) formed at the inner surface of the portion thereof coupled to the rotation frame (120), and which has an outer surface on which the fishing line is wound or unwound； a locking ball (130) mounted on the outer surface of the rotation frame (120) such that the locking ball is retractable or extensible； and elastic support means which elastically support the locking ball (130) such that the locking ball (130) extends from the outer surface of the rotation frame (120) to get caught, in a one-touch manner, at the locking protrusion (152) formed at the inner surface of the winding drum (150) when the winding drum (150) and the rotation frame (120) are coupled together.
