Spark plug

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.