Abstract: An automated driving system of a vehicle includes a driver monitoring unit configured to perform at least one of monitoring a gaze of a driver and determining a position of a hand of the driver, an automated-driving-level switching unit configured to determine whether a transition of a driving control over the vehicle is required based on whether driving environment of the vehicle has changed during the vehicle being driven under control of the automated driving system, and determine an automated driving level to be switched based on a driver monitoring result obtained by the drive monitoring unit, and an automated driving control unit configured to control the vehicle according to the automated driving level.