This invention relates to a method for operating a filter-tip rod machine and a filter-tip rod machine, wherein the filtering material is extracted from a storage, spread, extended and transmitted through the coating device, then provided to the forming apparatus, furthermore, a filtering material strip is formed to be a filter-tip rod. It is characterized in that at least one sensor identifies the default part and produces at least one signal after the extension of the filtering material strip and before the coating device, therefore, at least the area of the filter-tip rod with default parts will be excluded by the next process; the filter-tip rod has a filtering material output station, a spreading apparatus, a extending apparatus a coating device and a rod forming apparatus which helps making the filter-tip rod, wherein the apparatus comprises at least one sensor for identifying the default part of the filtering material strip, being characterized in that the sensor is arranged at the position of the extending apparatus or arranged at the lower part of the extending apparatus and the upper part of the coating device.