The invention provides an apparatus for processing an image of a face, capable of quickly and correctly detecting eyes not only under artificial illumination but also under sunlight regardless of the direction or altitude of the sun and regardless of circumstance conditions such as sunlight filtering down through trees, and still regardless of the variation in the face shape from person to person. An image of the face of a car driver is taken by a camera, and input to image signal input means. Gray level conversion means performs signal level conversion of picture elements of the face image received via the image signal input means in such a manner as to extract black-level areas smaller at least in the dimension along one image axis parallel or nearly parallel to the vertical direction of a face than a predefined length corresponding to the up-to-down width of an eye, thereby extracting black level areas having a size nearly equal to or less than the up-to-down width of the eye and thus extracting characteristic feature areas such as eyes, eyebrows, nares, and line between lips from the input face image. Variable binarization means converts the characteristic feature image into a binary image. Eye searching area setting means sets eye searching areas in the binary image. Candidate area setting means sets eye candidate areas in the eye searching areas. Eye area detection means detects eye areas from the eye candidate areas.