Abstract: The invention relates to continuous heat treatment of coiled tungsten filaments wound onto molybdenum cores, in the course of which said filament is passed first through a humid hydrogen atmosphere of about 1300.degree. C. then through a dry hydrogen atmosphere of a temperature of about 1700.degree. to about 1850.degree. C. The method complying with the invention is characterized by transfer times of the coiled tungsten filaments to be heat-treated through heating zones lying in the range of about 3 to about 7 seconds, preferably about 5 seconds, but the duration of passing through the 1700.degree. to 1850.degree. C. high-temperature is at most 7 seconds. The invention also covers the equipment suitable for accomplishing the method, consisting of two high-melting metallic heating tubes, an inventing wheel, a spiral winding/unwinding device, and a temperature sensing and controlling unit.