Packaging box

A packaging box comprising:

• at least a first wall portion and a second wall portion opposed to the first wall portion, wherein a shrinkable container filled with contents can be sandwiched between the first wall portion and the second wall portion whereby the shrinkable container can be held firmly between the first wall portion and the second wall portion due to a frictional force between an external surface of the shrinkable container and internal surfaces of the first wall portion and the second wall portion, a connection between the first wall portion and the second wall portion being continuous without an opening therein,
• wherein the first wall portion and the second wall portion are connected to each other with at least three wall portions, and, a third wall portion connected to a side opposed to a crossline between an extended plane of the first wall portion and an extended plane of the second wall portion can be opened by removing an anti-opening strip from an insertion opening,
• wherein a fourth wall portion and a fifth wall portion are provided to be connected to three wall portions of the first wall portion, the second wall portion, and the third wall portion, and the fourth wall portion and the fifth wall portion are tapered in a direction away from the third wall portion,
• wherein the packaging box is made of a single folded plate member, at least the first wall portion, the second wall portion, and the third wall portion are sequentially connected when developed into the packing box, the fourth wall portion and the fifth wall portion are connected to both sides of the first wall portion, and overlap portions for pasting the fourth wall portion and the fifth wall portion together are connected to both sides of the second wall portion, each overlap portion being formed so that a side of the overlap portion approximately coincides with a crease serving as a guide for folding the second wall portion toward the first wall portion.