The failure sign detection apparatus includes an abnormality detector to make a comparison between a failure detection parameter of a vehicle device mounted on a vehicle and a predetermined abnormality detection threshold, and make a determination whether there is an abnormality in the vehicle device based on a result of the comparison, a failure sign evaluation index calculator to calculate a failure sign evaluation index for evaluating a sign of failure of the vehicle device based on an abnormality duration period over which the detected abnormality continues and a parameter threshold difference indicative of a difference between the abnormality detection threshold and the failure detection parameter, and a failure sign detector to detect a sign of failure of the vehicle device based on the failure sign evaluation index calculated by the failure sign evaluation index.