PURPOSE: To remove the density unevenness of a positive electrode pellet and improve the characteristics of a battery by winding a positive electrode black mix round the diffused liquid drop of a bonding agent and granulating it while agitating the powder of the positive electrode black mix at a high speed.

CONSTITUTION: Each of graphite and a bonding agent is weighed and is mixed with MnO2 that is obtained by heat-treating the commercial γ-MnO2 in the atmosphere. These weighing and mixing are performed in a high speed agitating mixer. On the other hand, an aqueous solution of CMC is manufactured and is added bit by bit from the opening section on the mixer. The CMC aqueous solution is diffused in the mixer and is intertwined with the powder of a positive electrode black mix and then is granulated. Since the amount of water to be added is below a half, minute granulating particles are agitated in floating status.