A sheet electrode with a predetermined thickness for an electric double layer capacitor is made by carrying out a roller rolling step in which a long sheet intermediate is made from a material containing a carbonaceous powder, a conductive assistant and a binder and thereafter. The sheet intermediate is passed between a pair of rolling rollers to be wound up by a winding section while being drawn out of a drawing section. The roller rolling step includes drawing the sheet intermediate out of the drawing section under a predetermined tension applied to the sheet intermediate, and controlling a widthwise position of the sheet intermediate immediately before the rolling rollers by an edge position controller, and winding the sheet intermediate rolled by the rollers onto a winding section while the winding section is applying a predetermined pressure to a rolling side drive roller located adjacent to the winding section and rotated at a predetermined speed.