The abnormality detection apparatus includes a first function of measuring a first temperature of a first portion of the abnormality detection apparatus, the first temperature having a correlation with a second temperature of a second portion of a vehicle alternator, a second function of integrating a stress depending on a temperature variation of the first portion on the basis of the first temperature measured by the first function, a third function of predicting occurrence of abnormality in the second portion depending on the stress integrated by the second function, and a fourth function of issuing an alarm when the third function predicts occurrence of abnormality.