The separation of lanostane-type triterpene acids carrying an acetoxyl group from sclerotia of Poria cocos (hoelen) was effectively achieved by means of preparative HPLC of the phthalimidomethyl esters followed by selective hydrolysis of the phthalimidomethyl ester groupings. By this method, three new triterpene acids were isolated together with pachymic and dehydropachymic acids, which are characteristic compounds of hoelen. The structures of three new compounds were determined to be 3-o-acetyl-16α-hydroxytrametenolic acid, 3-o-acetyl-16α-hydroxydehydrotrametenolic acid, and 3-epidehydropachymic acid, respectively, based on spectroscopic evidence.