The results of anode potentials research under conditions of unipolar ECM by microsecond duration pulses was presented for iron, nickel, 40X13, 12X18H10T alloys in 8% NaCl and 15% NaNO3 aqueous solutions. Under applying of current pulse with short rise time, the anode potential was founded to be higher than potential of oxygen generation both in passivating NaNO3 and nonpassivating NaCl solutions. Increasing of current density results in appearing of two extremums (local maximum and minimum) on the “time-potential” curve. There are not such extremums in the same conditions for highpassivating metals, such as titanium and tungsten. The hypothesis was offered to explain the character of φ_a (j,t) dependencies on the base of two concurring processes: double layer charge and changing of its capacitance.