A spark plug has a center electrode, an insulator, a main metal fitting, and an earth electrode. The center electrode and/or the earth electrode has an intermediate member that connects the center electrode or the earth electrode to a noble-metal tip. The intermediate member has: a tip joint where the noble-metal tip is joined; and an electrode joint, which has a larger diameter than the tip joint and which is connected to the center electrode or the earth electrode. The intermediate member contains nickel (Ni) as a main component and has a chromium (Cr) content of 15 to 25 wt%. The surface of the intermediate member has a silicon (Si) content of 0.04 mg/mm3 to 0.12 mg/mm3 per unit volume and an aluminum (Al) content of 0.03 mg/mm3 to 0.10 mg/mm3 per unit volume.
