The purpose of the present invention is to provide a slurry composition for nonaqueous secondary battery positive electrodes, which exhibits excellent stability and is capable of forming a positive electrode mixture layer that enables a nonaqueous secondary battery to exert excellent output characteristics. A slurry composition according to the present invention contains a positive electrode active material and a copolymer, and is configured such that: the ratio of nickel in the transition metals contained in the positive electrode active material is from 30.0% by mole to 100.0% by mole (inclusive); and the copolymer contains from 70.0% by mass to 96.0% by mass (inclusive) of a nitrile group-containing monomer unit and from 0.1% by mass to 5.0% by mass (inclusive) of a basic group-containing monomer unit.