PURPOSE: To prevent the lowering of the dust-collecting capability of the titled dust collector, by detecting the static pressure in the dust-collecting duct, and cleaning the filter in the dust collector when the detected pressure exceeds a definite level.

CONSTITUTION: The foreign materials separated by the combing roller 4 of an open-end spinning machine are collected through the dust-separating chamber 7, the trash pipe 9, the dust-collecting duct 9, the blower 10 and the dust-collecting duct 9 to the dust-collecting chamber 12. In the above apparatus, a manometer 23 is inserted into the dust-collecting duct 9, and when the pressure detected by the manometer excceeds a preset level, the filter 11 in the dust-collecting chamber 12 is cleaned. The cleaning of the filter 11 is carried out e.g. by removing the foreign material and fly waste, etc. from the surface of the filter by scraper 14.