Abstract: A packaging box closing member includes a flat panel portion that is placed on a pair of unsealed lid portions of a packaging box so as to intersect a closed portion formed by the pair of lid portions, the pair of lid portions being located on a top surface of the packaging box; and an upright portion that stands on a side of the flat panel portion, the side intersecting the closed portion, wherein, when stacking another packaging box on the top surface of the packaging box, a part of the another packaging box or a part of a transport device that transports the another packaging box contacts the upright portion, and the packaging box closing member is pushed toward an end of the top surface of the packaging box together with the flat panel portion and is dropped.

Abstract: A packaging box closing member includes a flat panel portion that is placed on a pair of unsealed lid portions of a packaging box so as to intersect a closed portion formed by the pair of lid portions, the pair of lid portions being located on a top surface of the packaging box; and an upright portion that stands on a side of the flat panel portion, the side intersecting the closed portion, wherein, when stacking another packaging box on the top surface of the packaging box, a part of the another packaging box or a part of a transport device that transports the another packaging box contacts the upright portion, and the packaging box closing member is pushed toward an end of the top surface of the packaging box together with the flat panel portion and is dropped.