A method of manufacturing a lead-acid battery electrode, comprising the steps of: filling a paste-like active material onto a grid substrate made of a lead alloy to fabricate an active material-filled electrode; pressing the active material-filled electrode; and aging and drying the active material-filled electrode which has been pressed in the step of pressing to obtain an electrode that has not been chemically converted, wherein: the method further comprises: treating a surface of the active material-filled electrode with sulfuric acid that is adjusted to a constant temperature higher than an ordinary temperature; and preliminarily drying the active material-filled electrode, the surface of which has been treated with the sulfuric acid in the step of treating with sulfuric acid, before the active material-filled electrode is aged in the step of aging and drying, wherein: the sulfuric acid used in the step of treating with sulfuric acid has a temperature that is adjusted in the range of 40°C to 60°C, and has a specific gravity that is adjusted in the range of 1.10 to 1.30 (at a temperature of 20°C); the step of treating with sulfuric acid is included in the step of pressing; in the step of pressing, a roll pressing machine provided with a pair of rollers (9A, 9B) having pressing surfaces is used to press the active material-filled electrode by causing the active material-filled electrode to pass between the pair of rollers (9A, 9B); and the sulfuric acid is infiltrated into the press surfaces of the pair of rollers (9A, 9B) and the sulfuric acid is applied to the surface of the active material-filled electrode when the active material-filled electrode passes between the pair of rollers (9A, 9B). filling a paste-like active material onto a grid substrate made of a lead alloy to fabricate an active material-filled electrode; pressing the active material-filled electrode; and aging and drying the active material-filled electrode which has been pressed in the step of pressing to obtain an electrode that has not been chemically converted, wherein: the method further comprises: treating a surface of the active material-filled electrode with sulfuric acid that is adjusted to a constant temperature higher than an ordinary temperature; and preliminarily drying the active material-filled electrode, the surface of which has been treated with the sulfuric acid in the step of treating with sulfuric acid, before the active material-filled electrode is aged in the step of aging and drying, wherein: the sulfuric acid used in the step of treating with sulfuric acid has a temperature that is adjusted in the range of 40°C to 60°C, and has a specific gravity that is adjusted in the range of 1.10 to 1.30 (at a temperature of 20°C); the step of treating with sulfuric acid is included in the step of pressing; in the step of pressing, a roll pressing machine provided with a pair of rollers (9A, 9B) having pressing surfaces is used to press the active material-filled electrode by causing the active material-filled electrode to pass between the pair of rollers (9A, 9B); and the sulfuric acid is infiltrated into the press surfaces of the pair of rollers (9A, 9B) and the sulfuric acid is applied to the surface of the active material-filled electrode when the active material-filled electrode passes between the pair of rollers (9A, 9B). the method further comprises: treating a surface of the active material-filled electrode with sulfuric acid that is adjusted to a constant temperature higher than an ordinary temperature; and preliminarily drying the active material-filled electrode, the surface of which has been treated with the sulfuric acid in the step of treating with sulfuric acid, before the active material-filled electrode is aged in the step of aging and drying, wherein: treating a surface of the active material-filled electrode with sulfuric acid that is adjusted to a constant temperature higher than an ordinary temperature; and preliminarily drying the active material-filled electrode, the surface of which has been treated with the sulfuric acid in the step of treating with sulfuric acid, before the active material-filled electrode is aged in the step of aging and drying, wherein: the sulfuric acid used in the step of treating with sulfuric acid has a temperature that is adjusted in the range of 40°C to 60°C, and has a specific gravity that is adjusted in the range of 1.10 to 1.30 (at a temperature of 20°C); the step of treating with sulfuric acid is included in the step of pressing; in the step of pressing, a roll pressing machine provided with a pair of rollers (9A, 9B) having pressing surfaces is used to press the active material-filled electrode by causing the active material-filled electrode to pass between the pair of rollers (9A, 9B); and the sulfuric acid is infiltrated into the press surfaces of the pair of rollers (9A, 9B) and the sulfuric acid is applied to the surface of the active material-filled electrode when the active material-filled electrode passes between the pair of rollers (9A, 9B).