A packing member for packing an article, includes a medium accommodating portion for accommodating medium; a non-return valve for passing the medium to the medium accommodating portion and stopping the medium away from the medium accommodating portion; an introducing portion for introducing the medium into the medium accommodating portion with the non-return valve from an outside of the packing member to balloon the medium accommodating portion; and a sealing region, disposed upstream of the non-return valve with respect to a direction of the introduction of the medium from the introducing portion toward the non-return valve, for sealing against the introduction of the medium to prevent leakage from the introducing portion to an outside of the packing member, the sealing region being sealed to keep the medium in the medium accommodating portion.