An electrolytic paper for an electrolytic capacitor interposed between an anode foil and a cathode foil is made of cellulose fiber induced with organic substituent. The inducing reaction of the organic substituent is selected from etherification for hydroxyl group contained in the cellulose fiber, esterification for hydroxyl group contained in the cellulose fiber, or acetalization for hydroxyl group contained in the cellulose fiber. The swelling degree of the electrolytic paper made of this organic substituent induced fiber for electrolyte is increased.
