The reliability of detection of a driver's mental state in a vehicle in a driving state is enhanced without impairing operation stability of driving action of the vehicle. There are provided an imaging section 11 and a heart rate sensor 12 that serve as a plurality of detection means for detecting a driver's state; an appearance determination section 13 for determining a driver's appearance from detection results from the imaging section 11 and the heart rate sensor 12; and a mental state determination section 15 for determining a driver's mental state from the detection results from the imaging section 11 and the heart rate sensor 12. A switching section 14 switches the outputs from the imaging section 11 and the heart rate sensor 12 to an output from the mental state determination section 15 on the basis of a determination result from the appearance determination section 13.
APPARATUS FOR DETECTING DRIVER'S MENTAL STATE AND METHOD FOR DETECTING MENTAL STATE