A filter tipping machine wherein pairs of coaxial plain cigarettes are united with filter plugs of double unit length by adhesive-coated bands. When a filter plug is missing, a mechanical or a photosensitive filter plug detector transmits a signal to a valve which admits compressed air to two nozzles to cause the plain cigarettes which are not separated by a filter plug to move toward each other so that a uniting band which is applied around the adjacent inner end portions of the thus shifted plain cigarettes can adequately connect the plain cigarettes to each other during further transport to a station where the united plain cigarettes can be readily segregated from satisfactory products.