The invention relates to the packaging field and particularly relates to a snapping device for a packaging box. The snapping device for the packaging box comprises a snapping rod, a snapping rod seat and a snapping button; the snapping rod seat is installed on a box body; the snapping button is installed on a box cover; two ends of the snapping rod are embedded into jacks of the snapping rod seat; the snapping rod and the snapping rod seat are in clearance fit; the middle of the snapping rod is bent to be in a U shape; the top of the snapping rod is externally bent into a circular ring; the diameter at the outer end of the snapping button is slightly larger than that of the circular ring; the inner end of the snapping button is internally sunken. When the packaging box is closed, the circular ring portion of the snapping rod is sleeved onto a sunken portion of the snapping button, and the packaging box is in a snapping state and the packaging box can be opened when the snapping rod and the snapping button are separated.