A method of manufacturing an electronic device comprises forming a wiring material layer made of aluminum or an aluminum alloy on the surface of an insulating film on a substrate, patterning the wiring material layer by a reactive ion etching treatment with a resist pattern used as a mask so as to form a wiring, and treating the surface of the insulating film including the wiring with an aqueous solution for removing the etching residue, the aqueous solution containing a peroxosulfate, a fluorine-containing compound and an acid for adjusting the pH value and having a pH value of −1 to 3.