Abstract: The present invention provides a model animal for establishing an effective therapy for a protein aggregation disease typified by Alzheimer's disease and the like. More specifically, the present invention provides the followings: (A) a non-human animal that exhibits a degenerative symptom attributed to protein aggregation, wherein the degenerative symptom attributed to protein aggregation is induced by misfolding of the protein and said degenerative symptom is promoted; and (B) a method for producing the non-human animal that exhibits the degenerative symptom attributed to the protein aggregation, comprising the following (1) and (2): (1) inducing misfolding of the protein to cause the degenerative symptom attributed to the protein aggregation in the non-human animal, and (2) giving a treatment to promote the degenerative symptom attributed to the protein aggregation in the non-human animal.