Disclosed is a method for preparing an R- or S-forms of null-substituted heterocyclic carboxylic acid (null-HCCA) and a counter enantiomeric form of null-substituted heterocyclic carboxylic acid ester thereto by use of an enzyme. A racemic null-HCCA is reacted with alcohol to give a racemic null-HCCA ester, which is then brought into contact with an enzyme with enantioselectivity, whereby either R-form or S-form of the racemate is hydrolyzed. Extraction with an organic solvent can obtain enantiomers of the null-HCCA ester. Thus, a certain enantiomeric form of null-HCCA and a counter enantiomeric form of null-HCCA ester thereto, respectively can be prepared with high optical purity at high yields as well as at low cost.