A traffic lane marking line recognition system for vehicle includes an image compositing device which composites images photographed at different time points by a camera to elongate a traffic lane marking line such as a white line in the photographed image based on a detected travel speed of the vehicle. At least one image, among the plurality of images, photographed at a past time point earlier by a time interval determined in accordance with the vehicle speed from a reference time point, when defining a photographed time point of a given one of the images to be composited as the reference time point, is selected as the image to be composited with the given one of the images. By selecting the image to be composited in accordance with the vehicle speed, the traffic lane marking lines can be recognized unerringly.