For the excitation of spectrum of copper in argon atmosphere by spark discharge in a wide range of low voltage, a spectrochemical source unit is used, with which the relation of electrode erosion to other factors involved in the analysis is examined.The electrode erosion is obtained by the difference in weight of the electrode before and after the discharge. Under various discharge conditions, . the cathode electrode erosion is found linearly related to the integrated discharge current ∫idt. It affects also the spectral intensity but not the electron temperature which was measured by Ornstein's method. Except for the case of oscillating discharge, the anode electrode erosion was not observed.