Abstract: A laser machining device includes: a broadband light source, which generates a broadband laser beam; a first lens unit to which the broadband laser beam is incident and having a first effective focal length; a second lens unit spaced apart from the first lens unit in a first direction and having a second effective focal length; a beam splitter disposed between the first lens unit and the second lens unit, and which is movable in the first direction and a direction opposite to the first direction within the first effective focal length from the first lens unit, and splits the broadband laser beam passing through the first lens unit into a plurality of sub-laser beams; and a focusing lens spaced apart from the second lens unit in the first direction, and which focuses the sub-laser beams passing through the second lens unit on a substrate.