An electrode wear amount predicting system of a spark plug, includes: at least one ignition coil that includes a primary coil and a secondary coil; a spark plug that generates a spark discharge by a discharge current generated by the ignition coil and includes a center electrode and a ground electrode; a sensing portion measuring a current applied to the primary coil; and a controller that determines a wear state of the center electrode and the ground electrode according to an amount of the current applied to the primary coil detected by the sensing portion when an electrode wear amount predicting condition is satisfied.