Abstract: Unlike related art in which a variety of recycling aluminum materials are directly inputted into a pre-rolling melting furnace, the present invention provides the step of melting used planographic printing plates roughened by hydrochloric acid-based electrolysis in another melting furnace into a recycled metal ingot having a predetermined shape and weight and the step of using the results obtained by analyzing the recycled metal ingot to determine the mix proportions of the recycled metal ingot, the fresh metal ingot, and the trace metal master alloy to be inputted into the pre-rolling melting furnace. As a result, the amount of CO2 produced at the time of manufacture can be greatly reduced, and an aluminum plate having an aluminum purity of 99.0% or higher, which is required in a hydrochloric acid-based electrolytic roughening, can be manufactured.