Method for producing hypochlorite

Provided is a production method by which a high-concentration hypochlorite can be stably and efficiently produced by on-site production equipment at low cost, and which enables the production equipment to be compact. A method wherein: electrolysis is carried out by supplying an aqueous alkali metal chloride solution to a positive electrode chamber (2) of an electrolytic cell (10), which is divided into the positive electrode chamber (2) and a negative electrode chamber (3) by an ion exchange membrane (1), and supplying purified water to the negative electrode chamber; and a positive electrode solution (6), a produced chlorine gas (7) and a produced aqueous alkali metal hydroxide solution (8) after the electrolysis are introduced into a reaction chamber (18), so that a hypochlorite is produced by a reaction among the positive electrode solution, the chlorine gas and the aqueous alkali metal hydroxide solution within the reaction chamber (18). An ion exchange membrane for the production of a high-concentration caustic alkali for electrolysis of common salt or potassium chloride is used as the ion exchange membrane (1), and water (11) is added to the positive electrode solution or the aqueous alkali metal hydroxide solution before introduction into the reaction chamber (18), or alternatively to the mixture of the positive electrode solution, the chorine gas and the aqueous alkali metal hydroxide solution introduced into the reaction chamber (18).