1. A stop line recognition device comprising: capturing means for capturing an image of front environment outside an own vehicle including a carriageway thereof; stop line recognition means for recognizing a stop line on the carriageway of the vehicle based on an image captured by the capturing means; traffic signal recognition means for recognizing a traffic signal in front of the carriageway of the own vehicle; and permission determining means for permitting the stop line recognition means to execute stop line recognition when the traffic signal recognition means detects that the traffic signal front closest to the own vehicle on the carriageway thereof is displaying red light.