A driving lane recognizer 1 is arranged to detect a white line 30 on a driving road 20 on the basis of an image taken of the driving road 20. The driving lane recognizer 1 sets a near region 41 and a far region 42 adjacent to each other along a vehicle traveling direction in the image, detects a length of white line 30 in each of the near region 41 and the far region 42, and determines a type of white line 30 on the basis of the length of white line 30 in the near region 41 and the length of white line 30 in the far region 42. This permits the recognizer to determine the type of white line 30 on the basis of one image and to determine the type of white line 30 without use of past detection data or the like.