A method for manufacturing an aerosol product, wherein the aerosol product comprises an aerosol container comprising a container body and an aerosol valve or a valve assembly fixed to an opening of the container body, and an aqueous concentrate and a propellant being filled in the aerosol container, wherein the aqueous concentrate comprises an active ingredient having reactivity with oxygen, the container body is composed of an outer container (11,16) and an inner container (14,17), the aqueous concentrate is filled in the inner container (14,17), the propellant is filled between the outer container (11,16) and the inner container (14,17), and the aqueous concentrate is pressurized through the inner container (14,17), characterized in that a) the method comprises the steps of: filling the aqueous concentrate in the inner container; then filling the propellant between the outer container and the inner container and fixing the aerosol valve; then discharging air in an injection passage of the aerosol valve; and then filling an inert ingredient through the aerosol valve so as to discharge the aqueous concentrate present in the injection passage into the inner container, such that the inert ingredient is present in at least a part of an injection passage or b) the method comprising the steps of filling the propellant between the outer container and the inner container and fixing the valve assembly; then discharging air in the inner container and an injection passage of the valve assembly; then filling the aqueous concentrate in the inner container through the valve assembly; and then filling an inert ingredient through the valve assembly so as to discharge the aqueous concentrate present in the injection passage into the inner container such that the inert ingredient is present in at least a part of the injection passage. a) the method comprises the steps of: filling the aqueous concentrate in the inner container; then filling the propellant between the outer container and the inner container and fixing the aerosol valve; then discharging air in an injection passage of the aerosol valve; and then filling an inert ingredient through the aerosol valve so as to discharge the aqueous concentrate present in the injection passage into the inner container, such that the inert ingredient is present in at least a part of an injection passage or filling the aqueous concentrate in the inner container; then filling the propellant between the outer container and the inner container and fixing the aerosol valve; then discharging air in an injection passage of the aerosol valve; and then filling an inert ingredient through the aerosol valve so as to discharge the aqueous concentrate present in the injection passage into the inner container, such that the inert ingredient is present in at least a part of an injection passage or b) the method comprising the steps of filling the propellant between the outer container and the inner container and fixing the valve assembly; then discharging air in the inner container and an injection passage of the valve assembly; then filling the aqueous concentrate in the inner container through the valve assembly; and then filling an inert ingredient through the valve assembly so as to discharge the aqueous concentrate present in the injection passage into the inner container such that the inert ingredient is present in at least a part of the injection passage.