1. A moving-object detection apparatus having a plurality of moving-object detection processing devices configured to detect a moving object on the basis of a motion vector computed by making use of a present image and a past image wherein said moving-object detection processing devices are set to operate differently from each other in at least one of the resolution of said present and past images, the time distance between said present and past images and the search area of said motion vector in order to detect said moving object, in which the plurality of moving-object detection processing devices includes a short-distance moving-object detection processing device to detect a moving object at a first distance, a medium-distance moving-object detection processing device to detect a moving object at a second distance, and a long-distance moving-object detection processing device to detect a moving object at a third distance, and in which the third distance is larger than the second distance which is larger than the first distance.