Driving assistance device and driving assistance method

An acquisition unit acquires a light path length rij corresponding to an emission direction of emitted light, which is surrounding information of a moving body obtained by using a laser radar mounted on the moving body, a traffic mirror information including a center position N of a traffic mirror on a map, and position information of the moving body on the map. Then, on the basis of the acquired traffic mirror information and the acquired position information of the moving body on the map, an extraction unit extracts a light path length acquired via the traffic mirror from the acquired light path length rij, and then calculates an object reflection position corresponding to the extracted light path length. This makes it possible to obtain surrounding information in a blind spot for a driver while increasing robustness with respect to the surrounding information, and thus advanced driving assistance can be implemented.