PURPOSE: To certainly remove dusts dropped in an electrodeposition cell and thereby to improve coating quality by providing a circulating path at an upstream side-bottom part of the electrodeposition cell and providing a filter in the path.

CONSTITUTION: The car body to be coated is carried by a conveyor 10 and is immersed in an electrodeposition liquid L from a carrying-in edge side, is then carried in the electrodeposition liquid L and then is carried out from an carrying-out edge side. The circulating path 25 which has a suction port 23 at the corner part composed of an upstream side edge wall 13 and a bottom wall 12 of the cell 11 and has a discharging port opening horizontally toward downstream side at the upper part of the edge wall 13 is connected to the electrodeposition cell. The electrodeposition liquid L is circulated by providing a pump P3 and a filter F3 in the circulating path 25. Dusts stagnating at the bottom part of the upstream side of the cell 11 are catched by the circulating path 25 and removed by the filter F3.