Patent ID: 7015633

Claim:
A spark plug comprising: a cylindrical metal housing; a columnar center electrode insulated from said metal housing and supported inside said metal housing; a ground electrode having a leg portion extending substantially parallel to an axis of said center electrode and bonded to said metal housing at one end, and an opposed portion extending from the other end of said leg portion in a direction substantially normal to the axis of said center electrode so as to be opposed to a distal end of said center electrode; and a columnar noble metallic firing tip bonded to at least one of the distal end of said center electrode and the opposed portion of said ground electrode so as to form a discharge gap, wherein said noble metallic firing tip includes a protruding portion formed partly on an outer circumferential surface of said noble metallic firing tip so as to protrude in the direction substantially normal to the axis of said center electrode, and said protruding portion is disposed in confronting relationship via said discharge gap with a distal end of said opposed portion of said ground electrode far from said leg portion.