According to the present invention, there is provided a process for producing lithium manganate particles having a high output and an excellent high-temperature stability. The present invention relates to a process for producing lithium manganate particles comprising the steps of mixing a lithium compound, a manganese compound and a boron compound with each other; and calcining the resulting mixture in a temperature range of 800 to 1050° C., wherein an average particle diameter (D50) of the boron compound is not more than 15 times an average particle diameter (D50) of the manganese compound, and wherein the lithium manganate particles have a composition represented by the following chemical formula: Li1+xMn2-x-yY1yO4+B in which Y1 is at least one element selected from the group consisting of Ni, Co, Mg, Fe, Al, Cr and Ti, and x and y satisfy the conditions of 0.03≦x≦0.15 and 0≦y≦0.20, respectively.