Reduction of endocochlear potential (EP) is one of the main causes of sensorineural hearing loss. In this study, we investigated changes in the EP using a mouse model of acute cochlear energy failure, which comprised severe cochlear lateral wall damage induced by the local administration of 3-nitropropionic acid to the inner ear. We also analyzed the correlation between EP changes and histological findings in the cochlear lateral wall. We detected the recovery of the EP and hearing function at lower frequencies after severe damage of the cochlear lateral wall fibrocytes at the corresponding region. Remodeling of the cochlear lateral wall was associated with EP recovery, including the re-expression of ion transporters or gap junctions (i.e. Na/K/ATPase-β1 and connexin 26). These results indicate a mechanism for late-phase hearing recovery after severe deafness, which is frequently observed in clinical settings.