Abstract: A method for removing As, or As and Sb and/or Bi wherein acidic solution of sulfuric acid such as a copper electrolyte of having a free sulfuric acid concentration of less than 700g./l. and containing at least arsenic among arsenic, antimony and bismuth as impurities is warmed to be above 50.degree. C. or preferably above 60.degree. C. with the addition of H.sub.3 AsO.sub.4 in advance as required, one or a mixture of both of Sb.sub.2 O.sub.3 and Bi.sub.2 O.sub.3 preferably kneaded with water or the added solution is added to and mixed with the solution and the produced precipitate is separated to discharge the impurities out of the solution.