An update system includes an electronic control device that stores an autonomous driving logic and a server. The server includes: a storage unit storing personal characteristic data based on a user's driving and associated driving result data. In creating a first personal characteristic data associated with a first user ID and a first position, if first driving result data is present, the personal characteristic creating unit creates the first personal characteristic data using the first driving result data. If the first driving result data is not present, the personal characteristic creating unit creates the first personal characteristic data using the driving result data or the personal characteristic data associated with a user ID specified for the first user ID by the similarity specifying unit and the first position. The electronic control device includes a personal characteristic updating unit configured to update the autonomous driving logic using the first personal characteristic.