A process of producing a metallic foil by electrolysis by depositing the metallic foil on a cathode by electrolysis from a sulfuric acid acidic solution is disclosed, which comprises using an electrode having a coating of an electrode active material containing a platinum group metal oxide as an anode and carrying out the electrolysis in an electrolyte containing from 1 to 20 ppm of a lead component when a fluorine component does not exist in the electrolyte or an electrolyte containing from 0.2 to 1 ppm of a fluorine component and from 0.1 to 20 ppm of a lead component when a fluorine component exists in the electrolyte. The life of the electrode can be prolonged and a metallic foil can be stably produced by electrolysis for a long period of time by preventing the lead component(s) derived from the raw material from mixing into the metallic foil.