A device for stabilized opening and closing of a sliding panel includes a gear-like driving roller made of synthetic resin and provided with a number of low profile teeth arranged with a fin and constant pitch. The driving roller is arranged on the inside of the device and a pinch roller is arranged on the outside of the device in juxtaposition with the driving roller. A rack-like plate made of synthetic resin and arranged horizontally all the way along on the inner side wall of a sliding panel is engaged with and driven by the driving roller. A biasing device arranged at least on one of the driving roller or the pinch roller biasing it toward the sliding panel.