Acid-neutralizing agent contains substantial amount of calcium of an acid-neutralizing ability against various acid chemicals substance for humans, animals, agricultural produces, meat and poultry. And the method of producing the same are provided. An environmental friendly high speed and high press scraping treatment is applied to a calcium-containing substance represented by calcium carbonate-containing substances originating from shellfishes, to eliminate heavy metals and other contamination accumulated on the surface. A heating and baking treatment is applied separately to the different said shellfishes and calcium carbonate-containing minerals and charcoal of bamboo to the temperature and maintaining the temperature not less then the decompose point of each calcium component-containing substance, a sufficient time of heating and baking treatment from 3 hours up to 18 hours depend on materials treated. An ionization and stabilization process is applied to the decomposed calcium components substance in high temperature. A regular pulverizing process is applied to grind the said calcium-containing substance into 500 mesh sizes of powder. A Nano pulverizing process is applied to the said powder into sizes not larger then 18000000 mesh (size of Nano). A formulation process is applied to the different pulverized calcium containing powder in different percentage to formulas which suitable for different applications.