1. An eyelid detection device comprising: a edge value calculator that calculates edge values for pixels constituting an image depicting a driver's eye; a evaluation value calculator that successively defines a fitting curve, one end of which coincides with an inner corner of the eye depicted in the image, and the other end of which coincides with an outer corner of the eye depicted in the image, and calculates an evaluation value indicating a degree to which the fitting curve coincides with an edge of an eyelid of the eye; a characteristic curve generator that generates a characteristic curve indicating change in the evaluation value, on the basis of computation results from the evaluation value calculator; a determinator that, in the case of detecting two peaks whose vertices are maxima of the characteristic curve, or in the case of detecting two peaks whose vertices are minima of the characteristic curve, determines whether or not an area on the image defined by the two peaks includes an area occurring because of a red-eye effect; and a setter that sets a reference position for the eyelid, on the basis of a determination result from the determinator.