The physiological and morphological changes in the inner ear of the mice induced by intravenous injection of M. chelonae were investigated. Evaluation of ABR were risen in liminal value, especially in high frequency. These changes began 3 days after injection. 14 days after injection, 35% of mice showed abnomal behavior, so-called “spinning disease”. Morphological damages in the cochlear and vestibular sensory cells were observed using SEM. In the organ of Corti, the inner and outer hair cell cilia had degenerated and disappeared. In the vestibular end organ, disappearance, fusion, and ballooning of the sensory hairs were observed and cross-links and rough nature of the sensory hair membrane have disappeared.