A method for processing a fluorine-containing electrolyte solution including a gasification step of gasifying a volatile component of an electrolyte solution including a fluorine compound by heating the electrolyte solution under reduced pressure, a fluorine immobilization step of immobilizing the fluorine component included in the gasified gas as calcium fluoride by allowing the fluorine component to react with calcium, and an organic solvent component collection step of collecting an organic solvent component included in the gasification gas, in which, preferably, after a small amount of water, aqueous mineral acid solution, or the like is added to the electrolyte solution, the volatile component of the electrolyte solution is gasified by heating the electrolyte solution under reduced pressure.