To provide a method of forming cellulose acetate tow fiber into a bale configured to include a sealed chamber with an internal volume in lower pressure relative to environmental atmospheric pressure.

In the method of packaging the elastic cellulose acetate tow fiber, the fiber is prepared, compressed and provided with an evacuator as a check valve thereon thereby forming a chamber which can be sealed, and the chamber is sealed and evacuated by way of the evacuator including release of compression with a density of 0.50-0.78 g/cm3 and an internal pressure of ≥16,000 and <101,325 Pa in the obtained bale.