[PROBLEM] To provide an information recording/reproducing apparatus, an information recording/reproducing method, an information recording/reproducing program and a record medium, secure contents are reproduced with a mobile device so that a check-out can be made on memory card of a small capacity thereby to prevent an authorized copy of the secure contents.[SOLVING MEANS] The information recording/reproducing apparatus creates a title key, encrypts the contents in accordance with a title key; stores the encrypted contents, stores navigation information on the reproduction of the contents containing the title key, encrypts the title key in accordance with the medium ID of an external medium, outputs the encrypted title key and an externally connecting method to the external medium, and transmits the encrypted contents stored, to the outside in case a request for the contents is received from the outside.