To establish a simple providing means of a positive electrode material for a lithium ion secondary battery minimizing the amount of impurities exerting a bad influence on battery characteristics, having high composition stability, and providing good battery characteristics.

A lithium-containing composite metal carbonate having a molar ratio of lithium to the total amount of metals of 0.5-1.3 and causing no pollution by S or lithium salts in which carbonate of metals and lithium carbonate are mixed (mixing of a hydroxide of Mg or the like is permissible) by adding an aqueous solution of a nitrate of Ni, Mn, or Co, or a mixture of the aqueous solution with an aqueous solution of a nitrate of Mg, Al, Ti, Cr, Fe, Cu, or Zr to a lithium carbonate suspension. The lithium-containing composite metal carbonate is used as a precursor for the positive electrode material. The precursor is used as the positive electrode material (an active material) in a simple method of an oxidation treatment.

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