Circulating folding type carton folding device

The utility model discloses a circulation folding type carton folding device which comprises a supporting device, a lifting device is fixedly installed in the supporting device, an extrusion device is fixedly installed at the side end of the lifting device, and the lifting device comprises a cross-shaped moving ring, a supporting threaded rod, a motor, an L-shaped connecting rod and a rotating side plate. The supporting threaded rod is fixedly installed in the center of the top end of the motor, the supporting threaded rod is sleeved with the cross-shaped moving ring in a threaded mode, the L-shaped connecting rods are symmetrically and fixedly connected to the side end of the cross-shaped moving ring, the rotating side plates are rotationally connected to the top ends of the L-shaped connecting rods, and the extruding device comprises a piston rod, a contact plate, an M-shaped air cylinder and an L-shaped piston rod. The contact plate is fixedly connected to the bottom end of a piston rod, and the piston rod