PURPOSE: A basidiomycete in Ustilago is cultured in an enriched medium to produce a large amount of coenzyme Q10 in high yield in a short time.

CONSTITUTION: A basidiomycete in Ustilago capable of producing coenzyme Q10 such as Ustilago cynodontis IFO-9758 or Ustilago mydis IFO-6907 is inoculated in an enriched medium containing saccharides, alcohols, organic acids or glycerol as carbon sources and aerobically cultured at 5W8.5pH and 15W35°C for 24W72hr, then the cell bodies are collected. The cell bodies are suspended in water and saponified with methanolic or ethanolic alkali in the presence of pyrogallol, then the coenzyme Q10 is shifted from the saponification solution into an organic solvent immiscible with water. The coenzyme Q10 is separated by adsorption or thin-layer chromatography to give the purified product.