The present invention provides a gene that can be used extensively in studies relating to resistant rice blast fungi. The gene codes for either one of the following proteins (a) or (b): (a) a protein consisting of the amino acid sequence shown in SEQ ID NO:2; or (b) a protein consisting of an amino acid sequence shown in SEQ ID NO:2 by deletion, substitution or addition of one or more amino acids, which exhibits scytalone dehydratase activity in the presence of a scytalone dehydratase inhibitor.