To prepare Cr-C alloy layers having high current efficiency, high Vickers hardness, and high brightness in electrodeposition on commercial cold-rolled steel plate, this study examined additives put into electrodeposition baths. From a Cr2 (SO4)3/(NH4)2SO4 aqueous bath containing oxalic acid and CrCl3/highly concentrated CaCl2/H3BO3 aqueous bath containing glycine, Cr-C alloy layers having high current efficiency, high Vickers hardness, and high brightness were formed. With the optimized bath compositions, the Cr-C alloy layers were produced with high current efficiency, high Vickers hardness, and high brightness. The highest current efficiency of 31.8% was obtained in a 0.4 mol kg-1 glycine/0.75 mol kg-1 CrCl3/4.68 mol kg-1 CaCl2/0.49 mol kg-1 H3BO3 bath. The Cr-C layers mainly comprised Cr3C2 and Cr7C3 alloys.