Abstract: An automobile window glass assembly for raising and lowering a window glass set in a door of an automobile includes a pair of guide rails secured to the door and having a longitudinally extending groove for guiding two opposing edges of the window glass. Guide rollers are secured to the two opposing edges of the window glass for being raised and lowered along corresponding ones of the guide rails. Each of the guide rollers includes a cylindrical roller consisting of a synthetic resin and secured to the head of a shaft fixed to the window glass, and a cap fitted into an open end portion of the cylindrical roller and having a freely elastically deformable portion contacting a surface of the groove of the corresponding guide rail at all times to assure that the window glass will not develop looseness or play in the direction of door width.