Spark plug

A spark plug comprising:

• an insulator having an axial hole extending along an axial line;
• a center electrode provided at a distal-side position inside the axial hole of the insulator;
• a metal shell provided on an outer periphery of the insulator;
• and
• a ground electrode including an end portion located on a distal side relative to the center electrode, the ground electrode being connected to the metal shell,
• wherein the ground electrode includes a parent material;
• a first core material provided inside the parent material;
• and a second core material provided inside the first core material and being made of a different material from the first core material,
• wherein the end portion includes a melt-formed portion in which part of the parent material is melted and that contains precious metal;
• and a discharge surface forming a surface of the melt-formed portion and facing the center electrode in a direction of the axial line, and
• wherein the melt-formed portion is in contact with the first core material and the second core material.