To improve an estimate accuracy in estimating a steady state of a driver. A heart rates R of the driver are recorded and the deceleration start time tg when a vehicle in a travelling state starts to decelerate and stops. The heart rates R within a predetermined period recorded before the deceleration start time tg by the biological information record unit (21) are referred to and a pre-deceleration heart rate Rb which is a representative value of the referred heart rates R is extracted. Furthermore, the heart rates R within a predetermined period recorded after the deceleration start time tg by the biological information record unit (21) are referred to and a post-deceleration heart rate Ra which is a representative value of the referred heart rates R is extracted. Then, the pre-deceleration biological information and the post-deceleration biological information extracted by the biological information extraction unit are compared with each other to estimate the steady state of the driver after deceleration. That is, when a difference ”R between the pre-deceleration heart rate Rb and the post-deceleration heart rate Ra is equal to or larger than a predetermined threshold value Rt, it is estimated that the driver after the deceleration in in the steady state.
