Disclosed is a therapeutic agent for polyglutamine disease or an inhibitor of the development of polyglutamine disease, which comprises, as an active ingredient, the following component (1) or (2): (1) (i) an HGF protein or (ii) a peptide which is a partial peptide of the HGF protein and which has substantially the same activities as those of the HGF protein, or a salt thereof； or (2) DNA comprising (i) DNA encoding the HGF protein, (ii) DNA encoding a peptide which is a partial peptide of the HGF protein and which has substantially the same activities as those of the HGF protein, or (iii) DNA which can hybridize with DNA having a nucleotide sequence complementary to that of the DNA (i) or (ii) under stringent conditions and which encodes a protein or peptide having substantially the same activities as those of the HGF protein.
