A control device that is mounted in a second vehicle which a first vehicle having a following travel function is detachably connected to or loaded on is provided. The control device includes a control unit configured to perform: detecting another vehicle that is within a predetermined range from the second vehicle in a state in which the second vehicle has the first vehicle connected thereto or loaded thereon and of which some or all of a scheduled travel route is the same as some or all of a scheduled travel route of the first vehicle after the first vehicle has been disconnected from the second vehicle; and transmitting following instruction information to the first vehicle and disconnecting the first vehicle from the second vehicle such that the first vehicle travels with the detected other vehicle as a preceding vehicle by the following travel function.