Abstract: A problem to be solved is to provide a packaging method suitable for transporting a cellulosic polymer, and another problem to be solved is to provide a packaging method suitable for transportation while suppressing the viscosity reduction of the cellulosic polymer. The cellulosic polymer is packaged so as to meet the following conditions (1), (2), and (3): (1) the packaging bag having a gas barrier property is filled with a cellulosic polymer; (2) an oxygen concentration in the packaging bag is adjusted to 0.8% or less and the packaging bag was sealed; and (3) when the packaging bag filled with the cellulosic polymer is placed such that the longest long side L is horizontal, the depth D of the packaging bag from the horizontal plane and the long side L satisfy the relational expression of 6.1?L/D?10.