A nonaqueous secondary battery having a positive electrode having a positive electrode mixture layer, a negative electrode, and a nonaqueous electrolyte, in which the positive electrode contains, as an active material, a lithium-containing transition metal oxide containing a metal element selected from the group consisting of Mg, Ti, Zr, Ge, Nb, Al and Sn, the positive electrode mixture layer has a density of 3.5 g/cm3 or larger, and the nonaqueous electrolyte contains a compound having two or more nitrile groups in the molecule.