An electrode material containing active material powder is prepared. Dry classification of the electrode material is performed by a classifier. An electrode is manufactured by using the electrode material subjected to the dry classification. The classifier includes a mesh screen, a blade, and a motor. Breakage of the mesh screen is detected by monitoring either or both of an operation sound of the classifier and torque of the motor. The electrode material contained in the classifier will no longer be used for manufacturing of the electrode when breakage of the mesh screen is detected.