Spark plug and method of producing the same

A spark plug, comprising:

• a housing having a cylindrical shape comprising a housing facing surface;
• an insulator having a cylindrical shape comprising an insulator facing surface, the insulator being supported in the housing;
• and
• a packing comprising an insulator side contact surface formed in contact with the insulator facing surface of the insulator, wherein
• the packing is arranged between the housing facing surface of the housing and the insulator facing surface of the insulator so as to face both the housing facing surface and the insulator facing surface,
• the cylindrical packing is comprised of a press-punched plate member that has already formed an inner circumferential press-sagging surface and an outer circumferential press-sagging surface, and
• each of the inner and outer press-sagging surfaces having a curved shape so as to be smoothly connected to the insulator facing surface of the insulator.