A lifting device comprising: a support member, a lifting assembly, comprising a swiveling wheel, a swiveling drive member, a mounting member and a first-stage sliding rail, wherein a flexible cable is provided to wrap around the swiveling wheel and moves with swivel of the swiveling wheel, and the flexible cable comprises flexible cable sections located on both sides of the swiveling wheel, the swiveling drive member is connected to the swiveling wheel and is adapted to drive the swiveling wheel to swivel, the mounting member is provided with a guide rail and a first fixed pulley, the first-stage sliding rail is adapted to slide upwards and downwards relative to the guide rail, and the first-stage sliding rail is fixed to the support member, and the flexible cable is provided to wrap around the first fixed pulley, and the flexible cable sections of the flexible cable located on both sides of the swiveling wheel are connected to the first-stage sliding rail; characterised in that one or more intermediate sliding rails are provided between the first-stage sliding rail and the guide rail, the first-stage sliding rail is mounted on the guide rail through the intermediate sliding rails, the intermediate sliding rails are provided with movable pulleys, and the flexible cable is provided to successively wrap around the first fixed pulley and the movable pulleys. wherein the intermediate sliding rails comprise: a second-stage sliding rail mounted on the guide rail and adapted to slide along the guide rail, wherein the second-stage sliding rail is provided with a first movable pulley and a second movable pulley, the first-stage sliding rail is mounted on the second-stage sliding rail and is adapted to move relative to the second-stage sliding rail, and the flexible cable is provided to wrap around the first fixed pulley, the first movable pulley and the second movable pulley successively; wherein the lifting assembly further comprises: a slider, fixed to the first-stage sliding rail and adapted to move in a straight line along the second-stage sliding rail, wherein the slider is fixedly connected to the flexible cable sections located on both sides of the swiveling wheel. a support member, a lifting assembly, comprising a swiveling wheel, a swiveling drive member, a mounting member and a first-stage sliding rail, wherein a flexible cable is provided to wrap around the swiveling wheel and moves with swivel of the swiveling wheel, and the flexible cable comprises flexible cable sections located on both sides of the swiveling wheel, the swiveling drive member is connected to the swiveling wheel and is adapted to drive the swiveling wheel to swivel, the mounting member is provided with a guide rail and a first fixed pulley, the first-stage sliding rail is adapted to slide upwards and downwards relative to the guide rail, and the first-stage sliding rail is fixed to the support member, and the flexible cable is provided to wrap around the first fixed pulley, and the flexible cable sections of the flexible cable located on both sides of the swiveling wheel are connected to the first-stage sliding rail; characterised in that one or more intermediate sliding rails are provided between the first-stage sliding rail and the guide rail, the first-stage sliding rail is mounted on the guide rail through the intermediate sliding rails, the intermediate sliding rails are provided with movable pulleys, and the flexible cable is provided to successively wrap around the first fixed pulley and the movable pulleys. wherein the intermediate sliding rails comprise: a second-stage sliding rail mounted on the guide rail and adapted to slide along the guide rail, wherein the second-stage sliding rail is provided with a first movable pulley and a second movable pulley, the first-stage sliding rail is mounted on the second-stage sliding rail and is adapted to move relative to the second-stage sliding rail, and the flexible cable is provided to wrap around the first fixed pulley, the first movable pulley and the second movable pulley successively; wherein the lifting assembly further comprises: a slider, fixed to the first-stage sliding rail and adapted to move in a straight line along the second-stage sliding rail, wherein the slider is fixedly connected to the flexible cable sections located on both sides of the swiveling wheel.