Abstract: The laser welding apparatus has a nozzle (10) for generating a transversely extending gas current (14) between the optical system (4, 5, 6) and the beam focus for the deflection of particles moving in a direction towards the optical system (4, 5, 6). In order to reduce the level of noise development and to improve the protective action of the gas current curtain (14), the receiving aperture (12) of a gas exhaust line (13) is disposed opposite the nozzle (10), and furthermore the nozzle (10) is provided within an injector envelope (11), which forms together with the gas exhaust line (13) a substantially continuous flow channel.