The present invention relates to a technology for providing pure chlorite (ClO_2^-), which does not include metal ions or metal salts in a chlorite aqueous solution which is used for sterilization, sanitation and water purification in indoor and outdoor places and environments where a sanitation condition is bad, or used as a disinfectant, a sterilizer and a fungistat during a food and water purification process. The technology of the present invention can be applied to a method and an apparatus for preparing a chlorite aqueous solution, which can be used with high efficiency by being supplied in a low cost structure to sterilization, water purification, food, and a field of requiring disinfection, sterilization, antibacterializing processes during various treating processes requiring sanitation by disinfection or sanitation treatment in places or environments where humans or animals live by obtaining a pure chlorite aqueous solution by a simple operation. The method of the present invention comprises: a chlorite dilution step of diluting chlorite in water; a positive ion removing step of removing positive ions by an ion exchange contact method of allowing positive ions of the chlorite diluted in the water to be in contact with a positive ion exchange resin using an underwater pump or powerless or spray gun or manual discharge pump device; and a concentration adjusting step of properly maintaining a concentration of a chlorite (HClO2) aqueous solution removed with the positive ions through processes.COPYRIGHT KIPO 2020본 발명은 실내?외 위생상태가 불량한 장소 및 환경에 소독이나 위생처리, 정수처리를 위해 사용되거나, 식품 및 정수 과정 중 소독, 살균, 제균제로 사용되는 아염소산 수용액 상에 금속이온(Metal ions) 내지는 금속염(Metal salts)이 포함되지 않는 순수한 아염소산(Chlorite, ClO2-)을 제공하기 위한 기술이다.본원 기술사상은 아염소산염을 물에 희석시키기 위한 아염소산염 희석단계와; 수중에 희석된 아염소산염의 양이온을 수중펌프 내지는 무동력 내지는 스프레이 건(Spray gun) 내지는 수동 배출펌프의 장치를 동원하여 양이온 교환수지와 접촉하도록 구성되는 이온교환 접촉방법에 의해 양이온을 제거하기 위한 양이온 제거단계와; 상기 공정을 통해 양이온이 제거된 아염소산(HClO2) 수용액의 농도를 적절히 유지하기 위한 농도조절단계를 포함하여 이루어지는 단순한 작업에 의해 순수한 아염소산