Patent ID: 8469759

Claim:
A method of manufacturing a spark plug which comprises: a center electrode; an insulator disposed externally of an outer circumference of the center electrode; a metallic shell disposed externally of an outer circumference of the insulator; and a ground electrode joined at one end portion to the metallic shell and disposed such that another end portion faces the center electrode; at least one of the center electrode and the ground electrode having a composite tip, the composite tip being configured such that a first tip and a second tip are joined together, the first tip forming a gap in cooperation with the center electrode or the ground electrode, the second tip connecting the first tip to the center electrode or the ground electrode; and the method comprising a joining process for joining the first tip and the second tip together by use of a laser beam, wherein the joining process comprises the steps of: (a) disposing the second tip on a support; (b) obtaining, after pressing downward at least the second tip by use of a pressing jig, a correction value for correcting a height of radiation of the laser beam; (c) correcting the height of radiation of the laser beam on the basis of the correction value; and (d) joining the first and second tips together by use of the laser beam.