A storage circuit of a portable device stores setting data concerning a function installed on a used vehicle or an in-use vehicle. Stored setting data of the portable device is read when the user gets in an in-use vehicle after use of a used vehicle. Setting data stored in the storage section of the vehicle apparatus is also read. The two read setting data are compared. When a comparison result shows a difference, execution of a function is permitted based on setting data read from the storage circuit of the portable device. The user can be notified of a function not used by the user or a new function when execution of the functions is permitted.