Provided are genes coding a protein having an ability of asymmetrically reducing a 2-oxo-4-phenylbutyrate to produce a (R)-2-hydroxy-4-phenylbutyrate advantageously from the industrial standpoint, the protein, and methods of producing a (R)-2-hydroxy-4-phenylbutyrate using them. Genes having a base sequence coding an amino acid sequence shown in SEQ ID NO:1, or a base sequence shown by a base sequence shown in SEQ ID NO:2.