1. A vehicle surroundings monitoring apparatus which detects objects existing around a vehicle from images obtained by a plurality of image sensors mounted on the vehicle, comprising: an object extraction process unit which extracts the objects from a predetermined standard image of the images obtained by a plurality of the image sensors; a driving environment detection process unit which detects a driving environment of the vehicle; and a standard image selection process unit which selects anew a standard image for use in the process of the object extraction process unit out of the images obtained by a plurality of the image sensors according to the driving environment detected by the driving environment detection process unit.