WELDING APPARATUS AND WELDING METHOD

PROBLEM TO BE SOLVED: To provide a welding apparatus which can efficiently and readily weld a material to be welded having a gap in a butt joint thereof and difficult to move as appropriate, and to provide a welding method.SOLUTION: A welding apparatus 1 includes: an oscillator 2 for generating laser light; a laser head 3 having an optical waveguide for guiding the laser light and capable of radiating the laser light to a butt joint surface of a plurality of materials B to be welded; a laser displacement gauge 5 for measuring surface profiles of the materials B to be welded; a laser head supporting device 6 that supports the laser head 3 and can change a relative direction between the materials B to be welded and the laser head 3 based on a measurement result of the laser displacement gauge 5 so that the laser light is radiated in a direction along the butt joint surface of the materials B to be welded; a camera 7 for capturing an image of a gap in the butt joint surface; and an arithmetic device 11 that obtains a size of the gap in the butt joint surface from the image captured by the camera 7 to determine a control rate of the laser head 3 and allows the laser light to be radiated to both material sides of the materials B to be welded.