PROBLEM TO BE SOLVED: To provide an arousal estimation device capable of suitably estimating arousal of an occupant.SOLUTION: An arousal estimation device (200) estimates arousal of an occupant based on a plurality of feature quantities showing a state of the occupant of a vehicle (10). The arousal estimation device is provided with: first estimation means (250) for estimating first provisional arousal of the occupant based on a first feature quantity with relatively less dispersion among the plurality of feature quantities； second estimation means (230) for estimating second provisional arousal of the occupant based on second arousal of the occupant based on a second feature quantity with relatively more dispersion among the plurality of feature quantities； correction means (260) for correcting a reference value which is used when the second estimation means estimates the second provisional arousal based on the first provisional arousal； and third estimation means (270) for estimating the arousal of the occupant based on the first feature quantity or the first provisional arousal, and the second provisional arousal.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2020,JPO&INPIT【課題】乗員の覚醒度を好適に推定することが可能な覚醒度推定装置を提供する。【解決手段】覚醒度推定装置（２００）は、車両（１０）の乗員の状態を示す複数の特徴量に基づいて、乗員の覚醒度を推定する。覚醒度推定装置は、複数の特徴量のうち、相対的にばらつきが少ない第１の特徴量に基づいて、乗員の第１暫定覚醒度を推定する第１推定手段（２５０）と、複数の特徴量のうち、相対的にばらつきが多い第２の特徴量に基づいて、乗員の第２暫定覚醒度を推定する第２推定手段（２３０）と、第１暫定覚醒度に基づいて、第２推定手段が第２暫定覚醒度を推定する際に用いる基準値を補正する補正手段（２６０）と、第１の特徴量又は第１暫定覚醒度と、第２暫定覚醒度とに基づいて、乗員の覚醒度を推定する第３推定手段（２７０）とを備える。【選択図】図１
