Provided is a method for producing a stabilized one-liquid hypobromous acid composition which includes substantially no bromate ions, and which exhibits excellent sterilization performance, excellent storage stability, and practically no corrosiveness with respect to metal. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid. The proportion of bromine added is not more than 25 wt% of the whole amount of the composition.
