1. A vehicle comprising: an imaging means; an image capturing means which captures a color image of a road via the imaging means; a specific-color-extracted image generating means which generates a plurality of specific-color-extracted images by performing a process of generating a specific-color-extracted image, which is obtained by extracting pixels of a specific color corresponding to the color of a lane mark in the road from the color image, with respect to a plurality of specific colors; and a lane mark detection means which detects the lane marks of the specific colors from a composite image based on the plurality of specific-color-extracted images generated by the specific-color-extracted image generating means.