PURPOSE: The titled apparatus of a reeling machine designed to prevent the reeling of a yarn out of a set fineness, in which a tension change is detected and transmitted to an operating member, and a driving member enlarges the movement of the operating member to operate a reeling stopping mechanism.

CONSTITUTION: A tension change of a yarn is detected by a detecting member 10, and transmitted to an operating member 11 via a string piece 13. A nail 21 of the operating member 11 is engaged with a nail wheel 12 to sway a swinging lever 20 positively. A swinging lever 22 is then turned reversely in a large way, and the engagement of a brake ring 24 with a cam surface 23 on the swinging lever 22 is released by the reversing motion of the lever 22 and the brake ring 24 is pressed to a friction drum provided at a reel 9 by a spring to apply a brake force and stop the reel 9.