We propose a novel electrophoretic wet classification method using the applied electric field strength as an operation parameter. The influence of the applied electric field, electrolyte concentration, and particle size on the electrophoretic mobility was directly evaluated by microscopic electrophoresis. For high electrolyte concentrations or small particles, the electrophoretic mobilities decreased with decreasing applied electric field, unlike the basic theory of electrokinetic phenomena. We then fabricated an electrophoretic classification device and investigated the separation efficiencies for various particle sizes, electrolyte concentrations, and applied electric fields. Finally, we performed a classification experiment using the applied electric field as an operation parameter. The applied electric field that provided the highest classification performance was the same as that where the difference in the separation efficiency was the highest. These results highlight the possibility of electrophoretic wet classification using the applied electric field strength as an operation parameter. (C) 2019 Elsevier B.V. All rights reserved.