METHOD laser welding apparatus and laser welding

Laser welding apparatus of the present application (10), while sequentially supplying the workpiece welding position having abutting surface, a laser welding apparatus for welding by laser beam irradiation of the interface butt of the workpiece, the laser light source (20) and the X · Y-axis scanner for scanning outputted laser beam LB in the X-axis and Y-axis directions orthogonal to each other (31) from the interface shape measuring apparatus butt for measuring a dimension along the interface (86) butt and (60), in order to weld by laser beam irradiation butt interface and (86a), a control device that drives and controls the X · Y-axis scanner (31) and (70), and the configuration of, of the workpiece butt shape of the interface by measuring with high accuracy, it is possible to laser weld the interface butt of the workpiece to high quality.