FIELD: manufacture of parts of sheet materials by laser welding, for example in industry branches for making automobiles. SUBSTANCE: method comprises steps of registering defects of butt welded joint at deep welding by means of laser beam due to continuously sensing height of seam along welded joint; sensing height of welded seam by means of mechanical pin or optical or acoustic range finder. Sensing device arranged over welded seam is provided with unit for continuously moving it along seam and it represents unit for remote measuring of distance till surface of welded seam. EFFECT: simplified system for detecting defects of welded seam at controlling one parameter, enhanced reliability of detection due to continuously sensing height of welded seam. 10 cl, 5 dwg
