| 主权项 |
1. A spark plug comprising:
a ground electrode including; a chip whose one end has a shape of a cylinder having a diameter from 0.8 to 1.2 mm and whose main component is a noble metal, and an electrode base material, to which a portion of the other end of the chip is joined through a fused portion where the chip and the electrode base material are fused; and a chip-and-base-material interface in which a surface of the other end of the chip and the electrode base material contact each other and which is surrounded by the fused portion, wherein, in a cross section passing through a center axis of the cylinder, a distance between an end point that is located on one side of the chip-and-base-material interface with respect to the center axis and an end point that is located on an interface between the chip and the fused portion that is exposed to the outside, is equal to or greater than 0.7 times the diameter, and the chip-and-base-material interface has a surface where an unmelted portion of the chip and an unmelted portion of the electrode base material abut each other. |
