A bagmaking and packaging device includes a transverse sealing unit, a first tube member, and a gas flow path member. The first tube member is disposed above the transverse sealing unit and extends in an up and down direction. The first tube member allows a packaging material to become wrapped around it to thereby form the packaging material into a tubular shape. At least part of the gas flow path member is disposed inside the first tube member. The gas flow path member delivers nitrogen into the packaging material formed into the tubular shape. The first tube member includes a cutout portion that extends in the up and down direction. The cutout portion is formed so that the nitrogen can move between a space between the packaging material formed into the tubular shape and the first tube member and the inside space of the first tube member.