SPARKPLUG

Peeling resistance of a noble metal chip is improved by reducing a difference in the thermal stress generated between the noble metal chip and a ground electrode. A spark plug 1 includes an insulator 2, a center electrode 5, a metal shell 3, and a ground electrode 27, wherein a spark discharge gap 33 is formed between the center electrode 5 and the noble metal chip 41 bonded to the ground electrode 27. The ground electrode 27 is provided with a concave hole portion 43, and 70% or more of the noble metal chip 41 is bonded to the hole portion 43 of the ground electrode 27 through a fusion portion 35 formed by fusing the noble metal chip and the ground electrode 27 to each other by emitting a laser beam or the like from the side surface of the noble metal chip. A gap 45 is formed between the noble metal chip 41 and at least a part of an inner wall surface 43S of the hole portion 43 so as to be more than 0 mm and equal to or less than 1.0 mm in the direction perpendicular to the central axis CL2 of the noble metal chip 41.