A cardboard box dividing device and a cardboard box production device are provided with: lower conveyors on which a plurality of connected cardboard box bodies are stacked and transported; a pressing device pressing the plurality of connected cardboard box bodies stacked on the lower conveyors from above; a cutting knife disposed along a width direction of the connected cardboard box bodies and dividing the plurality of connected cardboard box bodies stacked on the lower conveyors into a front part and a rear part; and a lifting/lowering device lifting and lowering the lower conveyors and the pressing device.