An eye part detecting device comprising: image acquiring means for acquiring an image including a face; and edge obtaining means for obtaining, from the image, a plurality of horizontal edges each comprising a sequence of pixels of horizontally varying luminance, and a plurality of vertical edges each comprising a sequence of pixels of vertically varying luminance, eyelid candidate determination means for labeling the plurality of vertical edges as lateral minus edges and lateral plus edges and the plurality of horizontal edges as longitudinal minus edges and longitudinal plus edges, and labeling the lateral minus edges as upper eyelid candidates and the lateral plus edges as lower eyelid candidates if they meet conditions with regard to length, direction, change from light to dark resp. dark to light, and positional relationship to other edges; the eyelid candidate determination means further for calculating the length and center of gravity of the vertical edge of the upper eyelid candidates and the vertical edge of the lower eyelid candidates; characterized in: lower eyelid candidate evaluating means for excluding lower eyelid candidates which have at least one horizontal edge present in the lateral directions from the center of gravity of the respective lower eyelid candidate; and upper-and-lower eyelid pair determination means for selecting, as an upper-and-lower eyelid pair, a combination of combinations of the upper eyelid candidates and the remaining lower eyelid candidates by determining that an absolute value of a difference between the length of the vertical edge of the upper eyelid candidates and the length of the vertical edge of the lower eyelid candidates, a horizontal distance between the center of gravity of the vertical edge of the upper eyelid candidates and the center of gravity of the vertical edge of the lower eyelid candidates, and a distance between the center of gravity of the vertical edge of the upper eyelid candidates and the center of gravity of the vertical edge of the lower eyelid candidates fall within predetermined ranges. image acquiring means for acquiring an image including a face; and edge obtaining means for obtaining, from the image, a plurality of horizontal edges each comprising a sequence of pixels of horizontally varying luminance, and a plurality of vertical edges each comprising a sequence of pixels of vertically varying luminance, eyelid candidate determination means for labeling the plurality of vertical edges as lateral minus edges and lateral plus edges and the plurality of horizontal edges as longitudinal minus edges and longitudinal plus edges, and labeling the lateral minus edges as upper eyelid candidates and the lateral plus edges as lower eyelid candidates if they meet conditions with regard to length, direction, change from light to dark resp. dark to light, and positional relationship to other edges; the eyelid candidate determination means further for calculating the length and center of gravity of the vertical edge of the upper eyelid candidates and the vertical edge of the lower eyelid candidates; lower eyelid candidate evaluating means for excluding lower eyelid candidates which have at least one horizontal edge present in the lateral directions from the center of gravity of the respective lower eyelid candidate; and upper-and-lower eyelid pair determination means for selecting, as an upper-and-lower eyelid pair, a combination of combinations of the upper eyelid candidates and the remaining lower eyelid candidates by determining that an absolute value of a difference between the length of the vertical edge of the upper eyelid candidates and the length of the vertical edge of the lower eyelid candidates, a horizontal distance between the center of gravity of the vertical edge of the upper eyelid candidates and the center of gravity of the vertical edge of the lower eyelid candidates, and a distance between the center of gravity of the vertical edge of the upper eyelid candidates and the center of gravity of the vertical edge of the lower eyelid candidates fall within predetermined ranges.