In an undazzled-area map product stored in a computer-readable storage unit, information indicative of a relationship between a boundary distance and each of a plurality of divided sections of a rectangular area to be picked up by a pickup unit is included. The pickup unit is provided in a reference vehicle with a headlight and working to pick up an image of the rectangular area ahead of the reference vehicle. The boundary distance is defined as a maximum distance between the reference vehicle and a target person such that, when a distance between the reference vehicle and the target person is within the maximum distance, the target person is estimated to be undazzled by the headlight of the reference vehicle.