1. A vehicle periphery monitoring apparatus, mounted on a vehicle, for recognizing a bicycle operated by a driver around the vehicle, comprising: an image capturing mechanism which captures an image around the vehicle to obtain a captured image having luminance values according to temperatures of an object; an extracting mechanism which extracts, from the captured image, an image region having luminance values indicating temperatures greater than a temperature of a background by a predetermined value; a bicycle determination mechanism configured to: determine whether a pair of first object portions each having a length in the vertical direction greater than a width in the horizontal direction is detected from the extracted image region; determine, if the pair of first object portions is detected, whether a distance between one of the first object portion and the other of the first object portion being less than a predetermined value; determine, if the distance is less than the predetermined value, whether a second object portion having luminance values different from the first object portions and having a length in the vertical direction greater than a predetermined value exists between the pair of the first object portion is detected from the extracted image region; and determine, if the second object portion is detected, an object including the pair of the first object portions and the second object portion as a bicycle.