SPARK PLUG

摘要

Provided is a spark plug wherein peeling of an electrode chip from a grounding electrode and a center electrode is suppressed. The spark plug (100) satisfies the conditions of 0.8=A1/A2=1.9, where A1 [Hv] represents the hardness of the electrode chip (70) which is present outside of the region within a range of a radius of 0.2 mm, and A2 [Hv] represents the hardness of the electrode chip (70) which is present within the range of a radius of 0.2 mm, with a boundary point (PA) between a molten pool (23) and the electrode chip (70) on the surface of the spark plug (100) at the center, on a cross-section that passes the center axis (O) of the electrode chip (70).