PURPOSE: To shorten the time for welding and to decrease the generation of weld defects by positioning an irradiation point to the surface of a solid material apart a prescribed distance from the joint surfaces of a sintered material and the solid material and inclining the axial line of a beam along the joint surfaces, then irradiating the surface of the solid material with the beam.

CONSTITUTION: Laser light 7 oscillated by a laser oscillator 1 is refracted by a bend mirror 2 and is stopped down by a condenser lens 3. The irradiation point 9 on the surface 5b of the solid material 5 apart from the joint surfaces 8 of the sintered material 4 and the solid material 5 is then irradiated by this beam. Welding is executed by rotating the solid material 5 around the axial center 5a. The welding in a short period of time is executed in this way and the generation of weld defects by blowholes is prevented.