PROBLEM TO BE SOLVED: To provide a new steroid 11&bgr;-hydroxylase useful for producing a 11&bgr;-hydroxysteroid such as a hydrocortisone.SOLUTION: There is provided a protein of (a1), (b1) or (c1): (a1) a protein including a specific amino acid sequence, (b1) a protein including an amino acid sequence in which one or some amino acids are deleted, substituted or added in a specific amino acid sequence, and having steroid 11&bgr;-hydroxylation activity, (c1) a protein including an amino acid sequence with a sequence identity of not less than 90% to a specific amino acid sequence, and having steroid 11&bgr;-hydroxylation activity.