An electrode according to the present invention employs the metal plate having the specified structure as the electrode substrate. The metal plate 51 has a plurality of protuberances 54 that are alternately protruded on both front and back sides thereof. Each of the protuberances 54 is formed in a pyramid shape in which an area of upper bottom 52 (a protruded part) thereof is smaller than that of a lower bottom 53. The upper bottom 52 in each of the protuberances 54 is formed with an aperture 56 having blanking burr 55 blinked in a substantially pyramid shape along a direction from the upper bottom 52 to the lower bottom 53 so that an opening 52a of the upper bottom part is formed in a polygon shape. Further, the size of each portions is set in accordance with c>s.gtoreq.0.1 mm.sup.2 and 0.2.ltoreq.h/d.ltoreq.0.95 where c is the area of the upper bottom of each of the protuberances 54, s is the area of the opening 52a of the upper bottom parts, h is the height of the blanking burrs 55 is h, and d is the total thickness of the electrode substrate before compressing.