1. An information processing apparatus comprising: an input unit configured to input an image; a face detection unit configured to detect a face of a person from the image input from said input unit; a first calculation unit configured to calculate a feature amount associated with an eye open/closed state from the face detected by said face detection unit; a second calculation unit configured to calculate, as a feature-change amount, a difference between the feature amount calculated by said first calculation unit and a feature amount calculated from a face detected from an image input before a predetermined time; and a third calculation unit configured to calculate an eye open/closed degree of eyes of the face detected by said face detection unit on the basis of the feature amount and the feature-change amount.