Patent ID: 8264131

Claim:
A spark plug comprising: a cylindrical insulating body which has an axial hole penetrating the insulating body in an axial direction; a center electrode which is inserted to a leading end portion of the axial hole; a cylindrical metal shell which is provided in an outer periphery of the insulating body; a ground electrode which is disposed at a leading end portion of the metal shell; and a noble metal chip which is bonded to a leading end portion of the ground electrode and forms a spark gap between the noble metal chip and a leading end portion of the center electrode, wherein the ground electrode has a hole corresponding portion with a concave hole portion in at least one of a leading end surface and a side surface of the leading end portion of the ground electrode, wherein 70% or more of a bottom surface of the noble metal chip is bonded to the hole portion of the ground electrode through a fusion portion formed by fusing the noble metal chip and the ground electrode to each other by irradiating a laser beam or an electron beam from a side surface of the noble metal chip, and wherein a space gap is provided between the noble metal chip and at least a part of an inner wall surface of the hole portion so as to be more than 0 mm and equal to or less than 1.0 mm in a direction perpendicular to a central axis of the noble metal chip.