Hitherto, spark plugs have been used for ignition in internal combustion engines, such as gasoline engines. In spark plugs, by bending a distal end face of a ground electrode towards an axial line of a center electrode such that the distal end face opposes the center electrode, a spark discharge gap is formed between the center electrode and the ground electrode. With the ground electrode joined to a metal shell, the ground electrode is bent towards the center electrode by using a bend spacer (refer to, for example, Japanese Unexamined Patent Application Publication No. 2005-243260).