An electrode substrate for a battery has nickel applied as a coat on the surface of a base constituted of crossing of a plurality of fibers including a core formed of synthetic resin and a coating of synthetic resin having a softening temperature lower than the softening temperature of the synthetic resin forming the core. The electrode substrate has the fibers of the base fusion-bonded at a cross point by heat treatment. The ratio of the coating occupying a II-II cross section of the fiber cross point is larger than the ratio of the coating occupying a fiber cross section (III-III cross section) at a site other than at the cross point.