The present invention provides a method for manufacturing a chlorous acid aqueous solution using salt as a raw material. The present invention provides a method for manufacturing a chlorous acid aqueous solution, the method including 1) a step for electrolyzing salt and obtaining a chlorate or an aqueous solution thereof, and 2) a step for reducing the chlorate or aqueous solution thereof and manufacturing an aqueous solution including chlorous acid. The method for manufacturing a chlorous acid aqueous solution includes a step for mixing an inorganic acid or an inorganic acid salt as a simple substance or two or more types thereof with the aqueous solution including chlorous acid, and then mixing any of an inorganic acid, an inorganic acid salt, an organic acid, or an organic acid salt as a simple substance or two or more types thereof.
