A cathode-depositing electrodeposition coating composition having excellent low-temperature curability comprising as essential ingredients

(A) 100 parts by weight of a reaction product of (11 a high molecular compound having a molecular weight of 500 to 5,000 and containing carbon-carbon double bonds with an iodine number of 50 to 500 and 3 to 12% by weight of oxirane oxygen, and (2) 30 to 300 millimoles, per 100 g of the high molecular compound (1), of a specified amine compound,
(B) 10 to 200 parts by weight of a reaction product of a specified diglycidyl compound with 1.9 to 2.1 moles, per molecule of the diglycidyl compound, of an alpha, beta-unsaturated carboxylic acid or an unsaturated fatty acid having a molecular weight of 100 to 350 and containing at least 10% by weight of a carbon-carbon double bond, or a mixture of both,
(C) 0.5 to 10 parts by weight of a reaction product of a high molecular compound having a molecular weight of 500 to 5,000 and containing a carbon-carbon double bond with an iodine number of 50 to 500 and 40 to 400 millimoles, per 100 g of the high molecular compound, of a specified alpha, beta-unsaturated dicarboxylic acid and
(D) 0.005 to 1.0 part by weight, as. I, of a water-soluble salt of an organic acid with a metal selected from manganese, cobalt, and copper.