A spark plug for internal combustion engines includes a third electrode (4) in addition to a center electrode (1) and a ground electrode (2) which define a normal or main spark gap (S₁). Defined between the center electrode (1) and the third electrode (4) is an auxiliary gap (S₂) adjoining the normal gap (S₁) and adapted to produce a capacitive discharge at a voltage lower than that of the normal gap (S₁), and a discharge is induced across the normal gap (S₁) by the capacitive discharge across the auxiliary gap (S₂).