Abstract: A method and apparatus for threading acrylic filaments on rollers of an oxidizing furnace, wherein (a) the atmospheric temperature in the furnace is maintained at 180.degree. C. to the oxidizing temperature, (b) the tips of said filaments are fastened to a filament-fastening bar spanning a pair of chains which engage chain wheels provided at both ends of each roller freely rotatable against the roller, (c) the chains are moved, thereby said filament-fastening bar attached to the chains being moved from the entrance to the exit of the furnace and the filaments being threaded on the rollers, and (d) the moving speed of the chains is controlled with progress of heat-treating of the filaments so as to match the behavior of shrinkage and elongation of the filaments.