SPARK PLUG

摘要

In the course of screwing a main fitting (50) having a Ni plating layer on the surface thereof into an attachment hole (91) and in a state where a stainless steel gasket (60) is sandwiched, but not compressed, between a projecting section (54) and the peripheral section (92) of the hole, each surface of the gasket (60) does not contact the other surfaces thereof. In a cross-sectional view of the gasket (60) taken along the direction of the axis (O) thereof, the gasket (60) and the projecting section (54) contact one another at a single point (X), the gasket (60) and the peripheral section (92) of the hole contact one another at a single point (Y), the point (Y) is located radially outward of the point (X), and the point (Y) is located radially inward of the maximum outer diameter (Dz) of the bearing surface (55) of the projecting section (54).