A miciroorganisim which produces compounds useful as an antifungal agent, particularly a therapeutic agent for deep-seated mycoses, such as mycotic sinusitis, is provided. The present inventors have conducted intensive studies on naturally-occurring microorganisms as a research for antifungal compounds, and found a fungus Acremonium persicinum which produces cyclic compounds having a potent antifungal activity and useful as a medicament, particularly an antifungal agent, and the present invention was completed.