decompression and cellulose sodium xanthogenate is obtained a diluted solution of sodium hydroxide is put in a container 24 shown in fig2 and the cellulose sodium xanthogenate is added in thereby the cellulose sodium xanthogenate dissolves in the solution of sodium hydroxide and forms a viscose solution 25 for the viscose solution 25 to contain 3 8 sodium hydroxide and 7 15 cellulose of the bamboo fiber 16 the input of the solution of sodium hydroxide and the cellulose sodium xanthogenate is previously adjusted next the viscose solution 25 is sent to an airtight container 28 via a pump 26 and a check valve 27 a plurality of nozzles 29 are provided at the bottom of the airtight container 28 each of the nozzles 29 is provided with a plurality 5 to 20 of small nozzle holes at intervals so that the viscose solution 25 inside the airtight container 28 may be ejected as filaments moreover compressed air is fed to the upper portion of the airtight container 28 so that the inside viscose solution 25 is pressurized and ejected from the nozzles 29 the viscose solution 25 ejected from the nozzles 29 is led into a deep tub 30 the deep tub 30 is filled with a dilute solution of sulfuric acid as a hardening bath wherein the viscose solution 25 cellulose sodium xanthogenate is hydrolyzed with the dilute sulfuric acid to be reconverted to cellulose and becomes fine and long regenerated cellulose fiber 31 viscose rayon furthermore in fig2 and 33 are switching valves to transfer the viscose solution 25 from the container 24 to the airtight container 28 via the pump 26 34 shows a pipe for compressed air 35 shows a screen for filtration to remove impurities in the viscose solution 25 36 shows an opening.