Traffic Signal Detection Device and Traffic Signal Detection Method

A traffic signal detection device includes a narrow-angle camera, a wide-angle camera having an angle of view wider than the narrow-angle camera, and a traffic signal detector configured to detect a traffic signal from at least any of a narrow-angle image captured by the narrow-angle camera and a wide-angle image captured by the wide-angle camera. The traffic signal detector selects, as a detection result, any of a traffic signal detected from the narrow-angle image and a traffic signal detected from the wide-angle image, on the basis of a deceleration start region in which a vehicle should start deceleration, the deceleration start region calculated from a position of a traffic signal with respect to the vehicle and a speed of the vehicle in order to stop the vehicle at a stop position with respect to the traffic signal.