Ultrasound vibrators (titanium stepped horns at 20 kHz) themselves were used as cathodes for electroreduction of benzaldehydes in a methanolic sulfuric acid solution. Three types of vibrating cathode were prepared by partitioning the surface of the horns with insulating materials : tip-section loop, lateral node and lateral loop cathodes. The current efficiency for reduction and product selectivity for the corresponding hydrodimeric products were increased with increasing ultrasound oscillating power in different manners on the cathodes. The lateral cathodes could exhibit the effect at relatively low ultrasonic powers compared with the sectional one. In addition, higher efficiency and selectivity were obtained at the lateral loop cathode than at the node one.