Ignition candle structure designed to provide improved durability and flammability of fuel

The spark plug consists of a central electrode (30), a ground electrode, a noble metal chip (45) connected to a surface of the ground electrode facing the central electrode by laser welding, and a fused portion that forms a weld of the noble metal pellet and the ground electrode. A section of the noble metal pellet traversing a length thereof is between 0.1 mm 2 and 0.6 mm 2. The percentage of a section of an unmelted portion of a connected end of the noble metal pellet in the range of a section of the noble metal pellet closest to the melt portion traversing the length of the pellet of noble metal is less than or equal to 50%. The angle that a straight line extending through the molten portion along a maximum depth of the molten portion with the surface of the ground electrode facing the central electrode is less than or equal to 60 ° .