An on-car-data recording apparatus mounted on a train to record image data, which is data of a video or an image photographed by an image pickup apparatus set in the train, including: a secret-key retaining unit that retains a secret key paired with a public key for electronic signature for which certification by a certification authority is completed, a train-specific-information managing unit that manages information specific to the own train capable of specifying a traveling position of the own train, an electronic-signature generating unit that integrates, the image data and the information managed by the train-specific-information managing unit, calculates a hash value of obtained integrated data, and generates an electronic signature on the basis of the calculated hash value and the secret key, and an image data managing unit that retains the generated electronic signature and the image data used in generating the electronic signature in association with each other.