PURPOSE: To prevent the falling-off of a guide roller by setting up a guide plate to an inside section on the longer side leg piece side of an unequal length "ko"(Japanese:katakana,2533)- shaped section guide rail body.

CONSTITUTION: One side leg piece 21a of the rail body 21 is extended to a section lower than the other side leg piece 21b in an upper guide rail 20, the guide rail 20 is formed to a "ko"(Japanese:katakana,2533)-shaped section of unequal length while the lower end of the other side leg piece 21b is bent inward to form a first bent piece 21c, and the L-shaped guide plate 22 with a second bent piece 22a, which runs parallel with an upper piece 21d and is opposed to the first bent piece 21c, is set up extending over the full length of the guide rail proper on the inside of one side leg piece 21a. The guide plate 22 is fixed integrally through welding, and fastened to the outer side 1a of the roof side rail 1 of a car-body side section. Accordingly, the guide rail is miniaturized while the guide rail is installed directly to the side surface of a car body.