A laser-welding head is capable of applying a fixed pressure to parts to be welded of workpieces regardless of the undulation of the surfaces of the parts to be welded. The laser-welding head includes a pressing device (12) having a roller (16) which rolls along parts of workpieces near a weld line (40) to press together the same parts of the workpieces, a pressing unit (6) for applying a predetermined pressure to the pressing device (12) to press the pressing device (12) toward the parts of the workpieces near the weld line (40), and a laser beam projecting unit (17) mounted on the pressing unit (6) for movement together with the pressing device (12). The pressing unit (6) is provided with a pneumatic cylinder actuator for applying the predetermined pressure to the pressing device (12).