An autonomous driving system includes at least one electronic control unit configured to set parameter among parameters, in response to an input by an occupant of a vehicle. The parameters are relevant to a traveling when the vehicle travels by an autonomous driving control. The at least one electronic control unit is configured to execute the autonomous driving control in accordance with the parameter. An autonomous driving system includes a canceling operation input unit to which the occupant inputs a canceling operation for the parameter. The at least one electronic control unit is configured to change the parameter to a regular value, when the occupant inputs the canceling operation to the canceling operation input unit after the parameter is set in response to the input by the occupant.