| 摘要 |
A spark plug (1) includes a center electrode (5), an insulator (2), a metallic shell (3), a ground electrode (27), and a noble metal tip (32) provided on at least one object member of the center electrode and the ground electrode. One end surface of the noble metal tip is joined to the object member via a fusion zone (35). The fusion zone includes a first fusion zone (351) formed through radiation of a laser beam or the like to the boundary between the object member and the one end surface of the noble metal tip along a perimetrical direction of the noble metal tip, and a second fusion zone (352) formed through radiation of the laser beam or the like from the side from which the laser beam or the like has been radiated in forming the first fusion zone, and intersecting with the first fusion zone. |
