A laser cutting device for cutting an original product includes a laser device which is movable along a first direction and a second direction perpendicular to the first direction, and rotatable reflecting mirrors. The original product includes a stub bar, optical lenses, and connection portions corresponding to the optical lenses. The rotatable reflecting mirrors correspond to the connection portions and are positioned above the original product and aligned with the connection portions. At least two rotatable reflecting mirrors are arranged in a straight line. The laser device is located on the straight line and is configured for emitting laser beams. Each of the rotatable reflecting mirrors is configured for reflecting laser beams from the laser device toward the corresponding connection portion and is configured for rotating so as to allow the laser beams from the laser device to reach the next rotatable reflecting mirror on the straight line.