Abstract: In arrangement of high speed plating system, a number of sequential treatment bath units are arranged side by side along an arcuate path at equal intervals, a rotatable transfer unit of workpieces is arranged at the center of the arcuate path to concurrently allocate different workpieces to different treatment bath units for different but concurrent treatments and loading and unloading units are annexed to the transfer unit as interfaces to adjacent systems in a continuous line of production. Arcuate arrangement of the treatment bath units well minimized space demand in a mill and use of the loading and unloading units assure easy and smooth combination of the plating system with adjacent systems.