The seal between the insulator and the center electrode is to be improved in a spark plug for an internal combustion engine comprising a shell (12), an insulator (16) located in the shell and composed of a sintered ceramic material, as well as a center electrode (18) and a terminal stud (22) that have an electrically conductive connection with each other and are located in the insulator. For this purpose, it is provided that a cermet (28) abuts the center electrode, the ceramic phase of which is composed of the same or a similar material as the insulator, and the metallic phase of which is composed of a material having good electrical conductivity. Since the material properties of the cermet are similar to those of the insulator—the thermal expansion, in particular, is same—a particularly good seal is created between the cermet and insulating body.