A single filament having a smaller number of counts produced by a single orifice spinneret in the production of nylon monofilament chemical fibers. The fineness is thicker than the single filament in the multifilament, and the molten synthetic resin is condensed by a fine flow of the raw liquid which is extruded through the capillary pores of the spinneret. Or spinning with a multi-hole spinneret (eg up to 50 holes), and then twisted into a monofilament bobbin by flawless stretching and splitting