1. An object detection apparatus which is mounted in a vehicle and detects an object in a surrounding area of the vehicle, the apparatus comprising: a detection part which detects an object in the surrounding area of the vehicle; a processing part which calculates, with respect to the object detected by the detection part, information containing at least two of information indicating a position of presence of the object, information indicating a moving direction of the object, and information indicating a moving speed of the object, as target information; and a determination part which determines, based on the target information calculated by the processing part, whether the object is a movable body other than an automobile depending on whether the object satisfies a predetermined condition; and which determines, when a result of the determination is that the object is the movable body, a risk of collision between the movable body and the vehicle by using a criterion based on an assumption that the object is the movable body.