SPARK PLUG FOR AN INTERNAL COMBUSTION ENGINE

Disclosed is a spark plug that prevents a sharp increase in resistance of a resistor and materializes an excellent load life performance. A spark plug (1) is provided with a resistor (7). The resistor (7) is formed by heat-sealing of a resistor composition (56) that contains, at least, a conductive material (43) and glass powder. The glass powder contains between 35.0 mol% and 69.8 mol% SiO 2 , between 15.0 mol% and 49.8 mol% B 2 O 3 , between 5.0 mol% and 20.0 mol% Li 2 O, and at least one additive selected from MgO, CaO, SrO, BaO, Na 2 O, K 2 O, ZnO, and ZrO 2 in a total of between 2.6 mol% and 25.0 mol%. Further, the total content of Li 2 O and the additive (s) in the glass powder is between 15.2 mol% and 45.0 mol%, and the ratio of the Li 2 O content to the total content of the additive(s) is between 1.3 and 5.0.