To provide a manufacturing method of a positive electrode mixture for manufacturing a battery that has excellent charge and discharge cycle characteristics by suppressing separation of the positive electrode mixture and the current collector due to the corrosion of the current collector.

In the manufacturing process of the positive electrode mixture by mixing a positive electrode active material made of mainly LiCoO2, a conductive material and a binder, the positive electrode mixture is coated on the current collector made of aluminum, and an oxidizing gas such as CO2 is bubbled in the positive electrode mixture exhibiting strong alkalinity, and the pH of the positive electrode mixture that is neutralized is adjusted to be 9.2 or more and 11.7 or less.