1. A facial expression recognition apparatus by comprising: an image input unit configured to input an image; a face detection unit configured to detect a face image of a person from an image input by said image input unit; a calculation unit configured to calculate a facial expression evaluation value corresponding to each facial expression from a face image detected by said face detection unit; an updating unit configured to update, based on the face image, a relationship between a facial expression evaluation value calculated by said calculation unit and a threshold for determining a facial expression set for the facial expression evaluation value; and a determination unit configured to determine a facial expression of the face image based on the relationship between the facial expression evaluation value and the threshold for determining a facial expression which is updated by said updating unit.