In a method for producing a bristle from thermoplastic polymers through injection molding, the molten polymer mass is injected under pressure into a bristle-molding channel of predetermined length having a predetermined cross-section along this length and the channel is vented during injection molding. To produce injection-molded bristles with excellent bending behavior, the magnitude of the injection pressure is adjusted in dependence on the cross-sectional extension of the bristle-molding channel such that a shear flow is generated with high core speed in the center of the molten polymer mass flow and large shearing effect due to wall friction of the molten polymer mass under distinct longitudinal orientation of the polymer molecules at least in the region of the molten polymer mass close to the wall, which is maintained along the channel wherein the channel is simultaneously vented along its length to support maintenance of the shear flow. A device for carrying out the method is also described.