A vehicle departure determination apparatus includes: an object detection device which detects objects present in a direction of travel of a subject vehicle, and detects a relative position and relative speed of the objects and the subject vehicle; a running state detection device which detects a running state of the subject vehicle; a speed detection device which detects a speed of the subject vehicle; an oncoming vehicle determination device which determines whether any of the objects serving as oncoming vehicles for the subject vehicle are present, based on the relative speed detected by the object detection device, and the speed of the subject vehicle detected by the speed detection device; and a departure determination device which determines whether or not the subject vehicle has departed from an appropriate route for the subject vehicle, or the oncoming vehicle has departed from an appropriate route for the oncoming vehicle.