A spark plug 1 has a center electrode 4 and a ground electrode 5 opposed to each other and causes a spark discharge to occur through application of a voltage between the center electrode 4 and the ground electrode 5 . Moreover, the center electrode 4 has a columnar main chip 10 provided at a distal end thereof by welding via a fusion portion 12 and an annular auxiliary chip 11 surrounding the fusion portion 12. Consequently, when a spark discharge occurring from the center electrode 4 is blown to the downstream side by the influence of a gas flow in a cylinder of an internal combustion engine, it is possible to suppress a cathode point from being formed in the fusion portion 12 since the fusion portion 12 is surrounded and thus protected by the auxiliary chip 11. As a result, it is possible to suppress wear of the center electrode 4, thereby extending the service life of the spark plug 1.