ALERT APPARATUS

An alert apparatus sets a determination area which is at a turning direction side of an own vehicle with respect to a longitudinal direction line of the own vehicle and extends forward from the own vehicle or from near the own vehicle when an angle condition that a moving direction angle corresponding to an angle defined by a longitudinal direction line of the own vehicle and a moving direction of an approaching vehicle is within a predetermined angle range, is satisfied (1704). The alert apparatus sets the determination area which is at the turning direction side of the longitudinal direction line and away forward from the own vehicle by a predetermined distance when the angle condition is not satisfied (1707).