Novel tetraterpenes 1 and 3 have been isolated from an Okinawan soft coral Sarcophyton glaucum and their structures have been deduced by means of spectroscopy and chemical transformation. Their carbon framework, presumably formed by Diels-Alder reaction of two cembranoids, has been found to be the same as that of methyl sartortuoate and methyl isosartortuoate.