It is intended to provide a model animal faithfully reproducing the pathogenic conditions of spinal and bulbar muscular atrophy, a method of screening a remedy for polyglutamine disease using the same, and a remedy for spinal and bulbar muscular atrophy. Namely, a nonhuman animal having the following characteristics (1) to (5) in its conditions or pathological findings: (1) showing progressive myoatrophy; (2) showing lowering in muscular power; (3) in immunostaining with the use of an anti-polyglutamine antibody, showing nuclear diffuse staining and nuclear inclusions; (4) in immunostaining with the use of an anti-androgen receptor antibody, showing nuclear diffuse staining and nuclear inclusions; and (5) showing a neurogenic change. A remedy for polyglutamine disease is screened by administering a test substance to this nonhuman animal and examining changes in its conditions or pathological findings. A remedy for spinal and bulbar muscular atrophy is prepared by using as the active ingredient a compound having an effect of inhibiting the secretion of testosterone.