An automated driving apparatus acquires a position relation between a vehicle in front and a host vehicle based on peripheral state data D_info. When an intervehicular distance D1 between the host vehicle and the vehicle in front in a front-and-back direction has a value smaller than a first predetermined value D1ref, it is estimated that a risk of appearance Risk_ap is low compared with a case in which the distance in the front-and-back direction has a value equal to or larger than the first predetermined value D1ref.