Method of manufacturing electrode complex for forming electrode of spark plug, and method of manufacturing spark plug

A method of manufacturing an electrode composite for forming an electrode of a spark plug, the electrode composite being formed by laser-welding a first electrode member and a second electrode member together, the method comprising the steps of:

• a first electrode member holding step of holding the first electrode member by a chuck of a chuck unit;
• an eccentric error detection step to detect an eccentric error between a position of an actual center axis of the first electrode member and a shaft of a base rotatable supporting the chuck of the chuck unit;
• a center axis position correction step of correcting the position of the actual center axis of the first electrode member when the eccentric error detected in the eccentric error detection step falls outside a tolerance range subsequent to the eccentric error detection step, said center axis position correcting step aligning the actual center axis of the first electrode member with an axis of the shaft of the base;
• a second electrode member supply step of supplying the second electrode member such that an end surface of the second electrode member comes into contact with an end surface of the first electrode member;
• and
• a laser welding step of welding outer circumferential edges of the end surfaces through which the first electrode member and the second electrode member are in contact with each other.