A laser cutting device, including a laser beam generation unit emitting a laser beam; an optical system on a traveling path of the laser beam; a laser main body providing a passage through which the laser beam travels towards a substrate after passing through the optical system; a suction unit coupled to a header of the laser main body and sucking impurities, the suction unit including a curved surface therein; and a collection unit connected to the suction unit and collecting discharged impurities, the impurities being discharged to the collection unit along the curved surface inside the suction unit.