To provide a method for producing a spinel-type lithium manganese multiple oxide powder which is spherical and solid particle, is small in specific surface area and excellent in crystallinity.

In the method for producing the spinel-type lithium manganese multiple oxide powder which is spherical and solid particle, is small in specific surface area and excellent in crystallinity, it is preferable to dissolve nitrates of Li, Mn and Cr or Fe into distilled water in a stoichiometric ratio and to subjec the resulting solution to spray-thermal decomposition at 800°C. At this time, the substitution amounts of Fe, Cr, Al, Co, Li, Ni, Zn, Cu, Mg and Ti are shown by following formula: LiMxM'yMn(2-x-y)O4 (wherein, M is at least one of Cr and Fe; M' is at least one of Cr, Fe, Al, Co, Li, Ni, Zn, Cu, Mg and Ti; 0.1 ≤ x+y≤ 0.4, 0 ≤ y ≤x, and 0.1 ≤ x ≤ 0.4).