UPDATING CONTROL DEVICE, CONTROL METHOD, AND COMPUTER PROGRAM

An update control device including: a communication unit configured to communicate with an on-vehicle control device via a transmission path including an in-vehicle communication line; and a control unit configured to cause the communication unit to transmit a request message when a target device defined below is unable to execute an update process for a control program, the request message requesting an alternative device, which is a non-target device defined below, to alternatively execute a part of the update process. Target device: an on-vehicle control device whose control program is to be updated. Non-target device: an on-vehicle control device whose control program is not to be updated.