PROBLEM TO BE SOLVED: To provide a driver condition estimation device capable of reducing the load required for information processing for sequentially creating a driver model and capable of increasing the speed for entire estimation processing of a drivers condition.SOLUTION: A target azimuth angle acquisition unit 21 acquires a drivers target azimuth angle. An actual azimuth angle acquisition unit 23 acquires an actual azimuth angle of a vehicle Ca. A steering angle sensor 17 acquires a drivers actual steering angle. A reference model setting unit 35 sets a driver model which is a reference driver model suitable for repetitive use as a reference model, the driver model defining an input-output relation of the driver by using an azimuth angle deviation which is a difference between the target azimuth angle and the actual azimuth angle as a drivers input and the actual steering angle as a drivers output. A reference model steering angle acquisition unit 37 acquires a reference model steering angle by inputting the azimuth angle deviation to the reference model. An arousal level estimation unit 41 estimates the drivers condition based on a reference model error calculated from a difference between the actual steering angle and the reference model steering angle.
