JPS6229147B

PURPOSE:To elevate reliability of seam welding without exerting bad influence on a metallic structure of a substance to be welded, by providing a reflection body on a rocking member provided on the upper position of an upper chip for pressing the substance to be welded, and reflecting a laser light downward. CONSTITUTION:On a receiving base part 8b of a lower chip 8 of a welder, a substance to be weled 9 is placed. A rocking lever 5 is turned counterclockwise, and the substance to be welded 15 is pressed and fixed by an upper chip 5. Subsequently, a reflection body 25 installd to a rocking member 24 is rock-operated slowly by simultaneously driving a driving motor 21 and a laser device. In this case, the laser light is reflected downward by the reflection body 25, and executes seam welding of constant bead length to a weld zone 9a through a condensing lens 26. In this case, even if there is a slight difference in thickness of the substance to be welded 9, the lower chip 8 moves round the supporting axis, and smoothly presses the substance to be welded 9.