Traffic signal detection device and traffic signal detection method

Provided is a traffic signal detection device comprising a narrow-angle camera 11, a wide-angle camera 12 having an angle of view wider than that of the narrow-angle camera 11, and a traffic signal detection unit 4 that detects a traffic signal on the basis of at least a narrow-angle image taken by the narrow-angle camera 11 or a wide-angle image taken by the wide-angle camera 12. The traffic signal detection unit 4 selects a traffic signal detected in the narrow-angle image or a traffic signal detected in the wide-angle image as a detection result on the basis of a deceleration-start region where a vehicle 5 should start deceleration in order for the vehicle 5 to stop at a stopping position with respect to a traffic signal, such region being calculated on the basis of the position of the traffic signal with respect to the vehicle 5 and the velocity of the vehicle 5.