Packaging box

A packaging box comprising:

• a body part having a rectangular bottom plate, first side plates erecting from one opposed edges of the bottom plate and second side plates erecting from other opposed edges, and provided with an opened upper surface;
• a pair of inner flaps connected to upper edges of the first side plates through fold lines and folded inside;
• and
• a pair of outer flaps connected to upper edges of the second side plates through fold lines, and folded inside and overlapped with the pair of inner flaps to close the opened upper surface;
• wherein each of the pair of inner flaps is provided with a first engaging part and each of the first side plates is provided with a first engaged part capable of being engaged with the corresponding first engaging part when the pair of inner flaps are folded and overlapped with the outsides of the first side plates;
• and
• wherein the first engaged part is a hand hole and the first engaging part is an insertion piece inserted into the hand hole.