A server includes a communication interface and a controller. The controller receives a reservation request for a vehicle from a first user via the communication interface, determines an importance level of the reservation request, and generates first reservation information for a vehicle to be used by the first user, the first reservation information including the importance level. In a case in which there is no vehicle to assign to the first reservation information, the controller compares the importance level of the reservation request with importance levels of other reservation information that already exists, and assigns, to the first reservation information, a vehicle that has been assigned to second reservation information which is from among the other reservation information and includes an importance level lower than the importance level of the reservation request.