The invention shows a spin-up device (11, 51) and a method for spinning up a spinning device (1, 101) for the continuous extrusion of molded bodies (3) from a spinning solution (6), containing a solvent and cellulose dissolved in the solvent, wherein the molded bodies are extruded from the spinning solution (6) through spinnerets (7) of the spinning device (1, 101) in the form of a loose spinning curtain (2), the molded bodies (3) of the loose spinning curtain (2) are combined into a molded body bundle (4) after the extrusion, and the molded body bundle (4) is, in a further step, fed to a draw-off member (10) of the spinning device (1, 101) in order to start a continuous extrusion of the molded bodies (3). In order to make the spin-up method simpler in terms of process technology and more reproducible, it is proposed to increase the tensile strength of at least some areas of the molded bodies (3) of the loose spinning curtain (2) after their extrusion and before combining them into a molded body bundle (4).