Patent ID: 8253313

Claim:
A spark plug comprising: a rodlike center electrode; an insulator provided around the center electrode; a cylindrical tubular metallic shell provided around the insulator; and a ground electrode which is joined at one end to the metallic shell and which forms at the other end a gap in cooperation with the center electrode, the ground electrode including a ground electrode base member which forms a front end surface and a side surface at the other end, and a rodlike noble metal tip which is embedded in the ground electrode base member, through resistance welding, such that the noble metal tip projects from the front end surface and the side surface and which has a facing surface facing the center electrode, the spark plug being characterized in that a direction along which the noble metal tip projects from the front end surface of the ground electrode base member coincides with a longitudinal direction of the noble metal tip and slants in relation to a center axis of the ground electrode base member; and an inclination angle θ of a center axis of the noble metal tip along the longitudinal direction in relation to the center axis of the ground electrode base member satisfies a relation 2°≦θ≦25°.