The present invention relates to an enzyme determining amino acid sequences of an enzyme involved in pyrethrin biosynthesis and a base sequence of the gene thereof; constructing vectors bearing the gene and transformants; and extractable from plant bodies producing pyrethrin by applying such creative techniques to plant bodies with faster growth aiming to provide a method to efficiently produce pyrethrin; and the enzyme is a gene encoding a protein of the following (i) or (ii): (i) a protein consisting of an amino acid sequence shown in Sequence No. 1; or (ii) a protein consisting of an amino acid sequence including one or more of a substitution, deletion, insertion, and/or addition of amino acid in the amino acid sequence shown in Sequence No. 1, in which the protein exhibits activity of pyrethrin biosynthetic enzyme.