A method of producing threads and fibers of synthetic materials uses a cylindrically-shaped body of the synthetic material which is allowed to rotate against a scratching tool and a peeling knife arranged to follow the scratching tool in the direction of rotation. The peeled-off curtain of parallel threads is stretched, possibly while being simultaneously heated, and possibly the threads are cut to form a staple fiber or are ground to a short-staple floccule. A device for carrying out the aforementioned method, has a turning mechanism, a foil-peeling knife secured to a carriage of the turning mechanism, and a scratching tool arranged to precede the peeling knife.