Patent ID: 8810118

Claim:
A spark plug comprising: a tubular insulator having an axial hole penetrating in a direction of an axis; a center electrode inserted into a tip end side of the axial hole; a tubular metal shell disposed at an outer circumference of the insulator; a ground electrode disposed at a front end portion of the metal shell; and a pillar body tip that includes one end face and another end face, the one end face being welded to the ground electrode, the other end face forming a gap with a front end portion of the center electrode, wherein the ground electrode includes a part where the tip is to be welded, a clearance formed between a plating layer and a part including a constituent material of the tip; the ground electrode includes a surface where the plating layer is disposed, the plating layer covering the surface excluding a formation part of the clearance in the surface of the ground electrode; and the clearance has a size A that is equal to or more than 0.01 mm and equal to or less than 0.5 mm.