Three lanostane-type triterpenoids, spiro-astraodoric acid (1), and astraodoric acids E and F (2 and 3), together with 6 known compounds (4–9) were isolated from fruit bodies of an edible mushroom, Astraeus odoratus. Compound 1 possessed an unusual spirocyclic lanostane triterpenoid structure. Their structures were determined by spectroscopic analysis and the absolute configuration of spiro-astraodoric acid and astraodoric acids was described herein. Cytotoxicity of the isolated compounds was tested against six human cancer cell lines.