To make is possible to continuously produce a black zinc electroplated steel sheet in an electrogalvanizing line by using an acidic electrogalvanizing bath contg. specific ratios of dextrin, dextran and cobalt compd.

The steel sheet on which the black zinc electroplated films of an L value of ≤35 are deposited at 1 to 200g/m2 thickness is produced without the execution of an anode electrolytic treatment and chromate treatment. Pulse currents of an off time of 1msec to 50sec and a duty ratio of 0.01 to 0.8 are passed to the steel sheet in the acidic electrogalvanizing bath contg. 0.01 to 10wt.% dextrin and/or dextran and the cobalt compd. of the amt. sufficient for co-precipitating 0.01 to 10wt.% Co in the plating film. The steel sheet is energized in the plating bath and is then immersed for 0.5 to 15sec without energization. The corrosion resistance of the black zinc electroplated steel sheet is further improved if org. resin films of 0.1 to 2μm thickness are applied thereon. Since the steel sheet is not subjected to the anodic electrolytic treatment, the degradation in the corrosion resistance does not arise.