In this study, the effect of cationic surfactant (benzalkonium chloride) on the transport of KCl through a sulfonated styrene-divinyl benzene cation-exchange membrane was investigated. The presence of benzalkonium chloride as the cationic surfactant, which interacts with the sulfonic groups on membrane surface, has to disturb the transport of K+ ions and directly gives responses in its chronopotentiogram. The electrodialysis of the cationic surfactant solution showed an irreversible monotonous increase of the total system potential due to the fouling phenomena. However, a small amount of cationic surfactant in the membrane surface vicinity was observed to give a fluctuating chronopotentiogram at the high current density. This fluctuation is started by a steep increase and followed by the decrease of potential, which finally relaxed to reach a steady state. This potential fluctuation is proposed to be the response of a structural transformation of surfactant micelles on the membrane surface under perturbation of the externally applied electric field, which is discussed and examined qualitatively in this report.