A slurry for a lithium ion secondary battery positive electrodes contains a positive electrode active material, a binder, a conductive material, and an organic solvent. The binder contains a nitrile group-containing acrylic polymer and a fluorine-containing polymer; and the viscosity ratio ((viscosity at a shear rate of 2 sec−1)/(viscosity at a shear rate of 20 sec−1)) of this slurry as measured by a coaxial double cylinder viscometer is 1.0-2.5. Positive electrodes produced using the slurry have excellent weight accuracy, and lithium ion secondary batteries produced with positive electrodes produced from the slurry have a high capacity and excellent cycle characteristics at high potentials. The produced lithium ion secondary battery is flexible and free from the occurrence of cracks in an active material layer when bent.