The embodiment of the invention provides a folding box. The folding box comprises a packaging box, wherein the packaging box comprises a first bottom wall, a first front wall, a first back wall, two first side walls and a first upper cover group which are connected with one another; a first standby structure is arranged between the first bottom wall and each first side wall; a plurality of foldinglines are arranged on the packaging box; the packaging box is switched between a first box body provided with a first columnar containing space and a first bag body provided with a first flat containing space through the selecting folding lines for folding. According to the technical scheme of the folding box, the packaging box is folded through selecting the folding lines, can be switched between a box body state and a bag body state, so that the packaging box has the functions of a box body-shaped packaging box and a bag body-shaped packaging box, a proper containing space is provided for articles to protect the articles, so that the added production cost caused by individual production is avoided during production, and the problems that the cost is increased and the inconvenience is generated during using due to the fact that different kinds of outer packing structures are adopted for users are avoided.