A vehicle system includes: a reprogramming slave device implemented by an electronic control unit (hereinafter “ECU”) to be a target of updating an update file of a program stored among a plurality of the ECUs; a reprogramming master device that transmits the update file to the reprogramming slave device to control the update of the program stored in the reprogramming slave device according to a request from a terminal operable by a vehicle user; and a determination unit determines the progress of update processing on the update file. A vehicle device functions as the reprogramming master that includes: an obtaining unit for obtaining the progress determined by the determination unit; and a notification command unit for commanding a notification medium to notify the progress obtained by the obtaining unit.