A soil isolate of actinomycete, strain No. 43871 produced a new antifungal antibiotic, candiplanecin. Pale brownish to yellow orange color of colonies on agar media, the formation of bottle-shaped, cylindrical sporangia bearing motile spores and the presence of meso-DAP and glycine in the cell wall ascribed this strain to genus Ampullariella. From its morphological characteristics together with the cultural and physiological features, this strain was determined to be a new subspecies of Ampullariella regularis and designated as Ampullariella regularis subsp. mannitophila subsp. nov.(FERM-P No. 5646). Production of candiplanecin was carried out by conventional submerged culture, in which 2 μg/ml as the highest antibiotic titer was obtained.