PURPOSE: To dispense with provision of traversing apparatus to a testing apparatus, by movably placing a testing apparatus for testing the yarn-ending of an ending apparatus on a traversing rail of a doffer and detachably connecting the testing apparatus with the doffer through a connecting means.

CONSTITUTION: A traversing rail 6 is placed on a winder 1 and a doffer 7 is traversed along the traversing rail. The traversing rail is provided with a testing apparatus 11 to judge the ending quality of the yarn ended with an ending apparatus 5. The testing apparatus 11 is detachably connected with the doffer 7 through a connecting means 12 to perform the control of traverse only from the side of the doffer. Since the testing apparatus is traversed together with the doffer, it does not inhibit the operation of the doffer.