1. A vehicle surroundings monitoring apparatus that extracts a body present in the surroundings of a vehicle as an object, based on an image captured by an infrared imaging device, comprising: a binarized object extraction device that extracts a binarized object from image data obtained by binarizing a gray scale images of the image; a search region setting device that sets a search region at the lower part of the lower end of the binarized object extracted by the binarized object extraction device; a vertical edge detection device that detects one or more vertical edges in the search region set by the search region setting device; an object type determination device that determines a type of object based on whether or not the vertical edge is detected by the vertical edge detection device; and a pedestrian recognition device that determines the type of object to be a pedestrian based on the one or more vertical edges detected by the vertical edge detection device indicating the existence of leg portions in the search region of the binarized object, wherein the pedestrian recognition device executes pedestrian recognition processing on the object subsequent to the object type determination device determining that the object is something other than a manmade structure.