PURPOSE: To obtain uniform and good results from unskilled workers and to cultivate an anaerobic mold simply and effectively, by putting a medium inoculated with an anaerobic mold in a sealed container and adding a culture atmosphere agent consisting of a specific disoxidant, a carbonic acid gas generating agent, etc. to the container.

CONSTITUTION: A medium inoculated with an anaerobic mold is put in a sealed container consisting of a bag 10, etc., obtained by superimposing two sheets of transparent, flexible, air-impermeable films 11 and 12 having one free end and sealing peripheral parts of three sides of the superimposed sheets by heat sealing 13. A culture atmosphere agent 30 consisting of (A) an oxygen absorbent 40 of iron type, (B) a hygroscopic or deliquescent alkaline earth metallic salt, (C) a carbonate and/or a hydrogencarbonate and (D) a component such as a solid substance which is treated with water to show acidity, etc., is added to the sealed container 10 and free ends of the bag 10 are hermetically sealed by the use of a sealing tool 20 which sandwiches the free ends of the bag and seals the ends to give a culture tool. The anaerobic mold is cultivated by using the culture tool.