Novel antibiotics useful as a remedy for fungal infections and a process for producing antibiotic TKR1912-I or pharmacologically acceptable salts thereof, which substances have such physicochemical properties that (1) the mass spectrum thereof according to FAB-MS has a peak of m/z of 559 ÄM+HÜ ; (2) the molecule bears 26 carbon atoms and no nitrogen atom; (3) the ultraviolet absorption spectrum thereof in methanol shows a terminal absorptions; (4) the main absorption wavenumbers of the infrared absorption spectrum according to the KBr method are 3430, 2920, 2850, 1740, and 1190 cm ; and (5) they are soluble in methanol, chloroform, and water, but are sparingly soluble in hexane.