1. A vehicle surroundings monitoring apparatus, comprising: an infrared image photographing device for photographing a gray scale image, a pedestrian leg characteristic value storing device for storing a characteristic value of a leg of a pedestrian, a binarized object extracting device for extracting a binarized object by binarizing the gray scale image, a leg judging device for judging whether the binarized object is the leg of the pedestrian or not, by comparing a characteristic value of the binarized object extracted by the binarized object extracting device with the characteristic value of leg of a pedestrian, and a pedestrian recognizing device for recognizing an object including the binarized object as a pedestrian when the binarized object is recognized as a leg of a pedestrian by the leg judging device.