0 is substituted with isoleucine, (0) amino acid substitution where 000th amino acid in the amino acid sequence shown by SEQ ID NO:0 is substituted with alanine and 000th amino acid is substituted with alanine, (0) amino acid substitution where 00rd amino acid in the amino acid sequence shown by SEQ ID NO:0 is substituted with serine, 0. an esterase which is characterized in that it has at least a partial amino acid sequence necessary for expressing the thermostable esterase activity among the amino acid sequence shown by SEQ ID NO:0 having amino acid substitution where 000th amino acid in the amino acid sequence shown by SEQ ID NO:0 is substituted with isoleucine, 0. an esterase which is characterized in that it has at least a partial amino acid sequence necessary for expressing the thermostable esterase activity among the amino acid sequence shown by SEQ ID NO:0 having amino acid substitution where 000th amino acid in the amino acid sequence shown by SEQ ID NO:0 is substituted with alanine