A method is provided which, by a simple process, separates and recovers pulp fibers from a used absorbent article that contains pulp fibers and a superabsorbent polymer. A used absorbent article is treated with an aqueous solution that contains greater than or equal to 0.05 mass % of at least one kind of terpene selected from the group comprising terpene hydrocarbons, terpene aldehydes, and terpene ketones and that contains a deactivating agent that can deactivate the superabsorbent polymer; the superabsorbent polymer is deactivated, the adhesive that bonds together the constituent materials of the absorbent article is dissolved with the terpene to decompose the absorbent article, the pulp fibers are discharged to outside of the absorbent article, and the pulp fibers are separated from the absorbent article and recovered.