A sunroof unit for a motor vehicle having a vehicle window arranged in the vehicle roof area and having at least one roller blind system below the vehicle window for partially covering the vehicle window, wherein the roller blind system has two guide rails aligned in the vehicle longitudinal direction and a flexible planar structure guided in lateral areas by the guide rails. The guide rails are fixed with regard to their distance from one another in a front end area and/or in a rear end area only indirectly by the vehicle window. The guide rails are each fastened using a fixing device to the vehicle window, and at least one fixing device is designed as a variable fixing device to permit a positive fixing of the respective guide rail relative to the vehicle window in one of several discrete relative positions with respect to a vehicle transverse direction.