The present invention provides a method for preparing an organic compound, which comprises a dehydration step of distilling off water from a polar organic solvent solution containing the organic compound and water to bring the concentration of water below a given level, wherein the dehydration step comprises distilling off water together with the polar organic solvent while adding a polar organic solvent to the solution, or comprises repeating several cycles of adding a polar organic solvent to the solution and then distilling off water together with the polar organic solvent. The present invention further provides the preparation of an organic compound, which enables efficient isolation of the target product in high isolated yield from a polar organic solvent solution containing the organic compound, water and, if necessary, a compound which produces, upon coming into contact with water or the like, a substance accelerating the decomposition of the organic compound.