In order to provide a culture medium eliminating variation by lot of component concentrations, the present invention provides a culture medium, and preferably a chemical-synthetic culture medium, imparting a proliferation ability to yeast that is equivalent to or greater than that of a YPD culture medium. A culture medium is provided which includes sugars as a carbon source capable of being assimilated by yeast; amino acids as a nitrogen source; vitamins; inositol; zinc ion (Zn2+); potassium ion (K+), and magnesium ion (Mg2+), and in which inositol concentration is between 50 and 10,000 mg/L.