To efficiently obtain folio acid useful as a medicine (raw material), a reinforcing agent for modified milk powder, a feed additive, an additive for culturing microorganisms, etc., by culturing a yeast having a folic acid-producing ability or a bacterium having a specific folic acid-producing ability and subsequently collecting accumulated folic acid from the culture solution.

This method for producing folic acid comprises culturing a yeast belonging to the genus Candida, Pichia, Torulopsis or Saccharomyces and having a folic acid-producing ability or a bacterium belonging to the genus Bacillus and having an ability to produce the folic acid in an amount of ≥1mg/ liter of the culture solution to accumulate the folic acid in the culture solution, and subsequently isolating and collecting the folic acid from the culture solution. Thus, the objective folic acid useful as a medicine, a raw material for medicines, a reinforcing agent for modified milk powder, etc., a feed additive for livestock, etc., an additive for culturing microorganisms, etc., is effectively obtained.