A nanofiber spinning method and device for producing a high strength and uniform yarn made of nanofibers. The device includes: a nanofiber producing unit (2) which produces nanofibers (11) by extruding polymer solution, prepared by dissolving polymeric substances in a solvent, through small holes (7) and charging the polymer solution, and by allowing the polymer solution to be stretched by an electrostatic explosion, and which allows the nanofibers to travel in a single direction; a collecting electrode unit (3) to which an electric potential different from that of the charged polymer solution is applied, and which attracts the produced nanofibers (11) while simultaneously rotating and twisting the nanofibers, and gathers them for forming a yarn (20) made of the nanofibers (11); and a collecting unit (5) which collects the yarn (20) passed through the center of the collecting electrode unit (3).