An additive for an organic conductor includes a naphthalene ring, at least two sulfonic acid groups bonded to the naphthalene ring, and at least one carboxy group bonded to the naphthalene ring. In the case where the number of the sulfonic acid groups is two, when the sulfonic acid groups are respectively referred to as a first sulfonic acid group and a second sulfonic acid group, and a carbon atom of the naphthalene ring bonded to the first sulfonic acid group and a carbon atom of the naphthalene ring bonded to the second sulfonic acid group are respectively referred to as a first carbon atom and a second carbon atom, the number n of carbon atoms present between the first carbon atom and the second carbon atom is three or less.