Although the reeler, an autosomal recessive mutant mouse with the abnormality of lamination in the central nervous system, died about 3 weeks of age when fed ordinary laboratory chow, this mouse could grow up normally and prolong its destined, short lifespan to 50 weeks and more when given assistance in taking paste food and water from the weaning period. Histopathological examinations of the brain of this mutant mouse revealed no significant age-related difference, suggesting that this mutation does not fundamentally obstruct the spontaneous growth despite the abnormality of the central nervous systems. This mutant mouse is advantageous for investigations on influences of the central nervous system on the aging process and longevity.