An image processing system and the like capable of improving recognition accuracy of a lane mark are provided. According to the image processing system of the present invention, a first processing unit (110) recognizes a lane mark candidate on the basis of the luminance of each pixel in a road image. Moreover, there are evaluated a first index which represents continuity of an edge of the lane mark candidate, a second index which represents conformance between the width of the lane mark candidate and a lane mark standard width, and a third index which represents uniformity of the luminance of pixels contained in the lane mark candidate. According to the first, second, and third indices, a second processing unit (120) recognizes a lane mark candidate most likely to be a true lane mark as a lane mark.