PURPOSE: To improve the aerodynamical properties and appearance, by allowing the lower end of a window glass to project to the outside of a car body as the window glass approaches the completely shut position.

CONSTITUTION: When the door glass G is lifted, the lower end of the glass G is lifted with it biased to a door outer panel 2 and along the lower arcuate section of a rail 10 of which curvature is approximately similar to that of the glass G and which is inclined outward until a slider 11 reaches a differently curved section 10A of the guide rail 10. When the door glass G approaches the completely shut position, the slider 11 reaches the differently curved section 10A, and then the slider passes it, the lower end of the glass G projects greatly toward the panel 2 as shown by locus lines a, b, and accompanied therewith the upper end of the glass G approaches the door weather strip 8 at an upper edge of the opening of the car body.