As for the driver state decision device which relates to this invention, deciding, whether or not specified handling of the car was done, the driver state decision device 1 which decides the state of the operator of our vehicle, when the flow phase which is detected by size detection means and the flow phase detection means which detect the flow phase detection means and the size detect the flow phase of our vehicle of the preferential vehicle which is located to the front of our vehicle exceeds specified threshold level, the preferential vehicle which is detected as those where consciousness of the operator of our vehicle decreases by conscious decrease decision means and the size detection means which it decidesAccording to size, it has with the threshold level configuration means which configurate the above-mentioned specified threshold level.本発明に係るドライバ状態判定装置は、所定の運転操作が行われたか否かを判定して自車両の運転者の状態を判定するドライバ状態判定装置1であって、自車両の走行状態を検出する走行状態検出手段と、自車両の前方に位置する先行車両の大きさを検知する大きさ検知手段と、走行状態検出手段により検出された走行状態が所定のしきい値を超えたときに、自車両の運転者の意識が低下したものと判定する意識低下判定手段と、大きさ検知手段により検知された先行車両の大きさに応じて、上記所定のしきい値を設定するしきい値設定手段とを備える。
