Problem to be solved: sleepiness estimation with little erroneous judgment.The wakefulness estimating device has an eye opening acquisition section for acquiring the opening of the eye of the subject. The wakefulness estimating device has a dispersion calculating section for calculating the variation of the opening of the eye within a predetermined time. The waking degree estimating device has a sleepiness judging section for performing sleepiness judgment using the calculated dispersion and a predetermined threshold value.Diagram【課題】誤判定の少ない眠気推定ができる。【解決手段】覚醒度推定装置は、対象者の眼の開度を取得する眼開度取得部を有する。覚醒度推定装置は、所定時間内の眼の開度のばらつきを算出するばらつき算出部を有する。覚醒度推定装置は、算出されたばらつきと所定の閾値とを用いて眠気判定を行う眠気判定部を有する。【選択図】図1
