This invention includes an annular hysteresis brake (34) having one end fixed to a stationary frame (11), a support shaft (6) extending through a hollow portion of the hysteresis brake (34), and a spindle part (4) rotatably supported by the support shaft (6). The hysteresis brake (34) includes a yoke (36), a cylindrical hysteresis member (46) inserted into an annular space (41) of the yoke (36), and a hub (37) for rotatably supporting the hysteresis member (46). The spindle part (4) is supported by the support shaft (6) such that the spindle part (4) is restricted from moving toward the hysteresis brake (34) by a sleeve (15). The spindle part (4) and hub (37) are coupled with each other so as to rotate together via pins (21). This invention can simplify the structure while preventing damage to the hysteresis brake, thereby reducing the manufacturing cost of a thread-supplying spindle unit.