An apparatus detecting driving incapability state of a driver includes: an inclination detection portion that detects inclination of a head of a driver with respect to a trunk of the driver lower than a neck, based on an image of a driver seat captured by an imaging device mounted on a vehicle; and a posture collapse detection portion that detects the driver is incapable of driving when the inclination of the head detected by the inclination detection portion is greater than a relative inclination threshold during travel of the vehicle.