To provide a winding tension control device that can appropriately adjust winding tension in association with a yarn slack-eliminating device during winding of a spun yarn.

A winding tension control device 8 incorporated into a spinning machine having a yarn slack-eliminating device 7 to control winding tension comprises a yarn path-bending guide 81 located close to and on downstream side of a slack-eliminating roller 71 to guide a yarn traveling from the slack-eliminating device 7 to a winding device 9 while bending a yarn path of the yarn, and a yarn path-bending guide-displacing device 82 that makes the yarn path-bending guide 81 to approach the slack-eliminating roller 71 to set an angle of the bending to a larger bending angle 1, when the winding tension is to be increased, while moves the yarn path-bending guide 81 way from the slack-eliminating roller 71 to set the angle of the bending to a smaller bending angle 2, when the winding tension is to be reduced.