Slurry is prepared by dispersing a solvent containing fibrous carbon (carbon nanotube, vapor grown carbon fiber (VGCF (registered trademark))) by using a media-type disperser, and the slurry to be applied to a collector is obtained by kneading the prepared slurry and an electrode active material. As a media-type disperser, for example, a ball mill disperser or a bead mill disperser is used. The dispersion using the media-type disperser is performed for 5 to 10 hours. As a dispersant, for example, at least any one of a nonionic dispersant, an ethylenic dispersant, a polymeric dispersant and an amine dispersant is used. The dispersion is performed so that a fiber length of the fibrous carbon becomes 2 to 7 μm.