Abstract: An apparatus for laying pre-stretched elastic threads in a curved path on a continuously advancing web of material includes at least one rotatable thread-guide roll. The roll is provided with a peripherally extending curved groove or slot whose axial amplitude controls the positioning of the threads on the web, and achieves the desired curvature of the threads. The apparatus further includes a glue applicator for applying adhesive to the threads. The roll may conveniently have the form of a tube provided with through passing slots for guiding the threads straight through the tube and laying them onto the web.