A spark plug 1 includes a cylindrical housing, a cylindrical insulator, a center electrode, a terminal bracket, a ground electrode, and a resistor. The insulator is held on the inside of the housing. The center electrode 4 is held on the inside of the insulator, with a tip end being projected therefrom. The terminal bracket is held on the inside of the insulator, with a base end part and being projected therefrom. The ground electrode forms a spark discharge gap G between itself and the center electrode. The resistor contains carbon and is disposed on the inside of the insulator so as to be located between the center electrode 4 and the terminal bracket. In an axial direction X of the spark plug, the resistor has a higher carbon content in a first region positioned on a tip side, compared to a second region positioned on a base end side.