The driver state determination device (100) includes a biological signal analysis unit (130) that calculates a feature amount used for estimating the driver's state from a biological signal of the driver of the vehicle (10), and based on the feature amount of the biological signal. Then, the driver state calculating unit (140) that calculates the estimated value of the state of the driver and the driver that classifies the state of the driver by comparing the estimated value of the state of the driver with a predetermined threshold value. A state classification unit (150) and an information presentation unit (160) that presents information to the driver according to the result of classification of the driver's condition. In the recording unit (141), has the driver's eyes closed degree, the route information of the vehicle (10), the in-vehicle environment information of the vehicle (10), and the operation of the vehicle (10) matched with the content of the information presentation performed? At least one of the information indicating whether or not the driver and the estimated value of the driver's state are recorded in synchronization with each other, and the threshold updating unit (142) is based on the information recorded in the recording unit (141). Then, the threshold for classifying the driver's state is updated. 運転者状態判断装置（１００）は、車両（１０）の運転者の生体信号から運転者の状態の推定に用いる特徴量を算出する生体信号解析部（１３０）と、生体信号の特徴量に基づいて、運転者の状態の推定値を算出する運転者状態算出部（１４０）と、運転者の状態の推定値を予め定められた閾値と比較することで、運転者の状態を分類する運転者状態分類部（１５０）と、運転者の状態の分類結果に応じて、運転者に情報提示を行う情報提示部（１６０）とを備える。記録部（１４１）には、運転者の閉眼度、車両（１０）の経路情報、車両（１０）の車内環境情報、および、情報提示の内容に合致した車両（１０）の操作が行われたか否かの情報のうちの少なくとも１つと、運転者の状態の推定値とが、互いに同期して記録されており、閾値更新部（１４２）は、記録部（１４１）に記録された情報に基づいて、運転者の状態を分類するための閾値を更新する。
