PURPOSE: To convey a heavy panel in a proper attitude without entailing any damage to its decorative surface even if it is too heavy by stopping both edges of the panel with a flange of a turning roller guiding a flat belt at time of conveying the panel in holding it between a movable side flat belt and a fixed side flat belt.

CONSTITUTION: When a panel is on standby at a feeding position, a movable side flat belt system 1b moves horizontally by means of a driver 2, and both ends of the panel P are held between the belt device 1b and a fixed side flat belt device 1a. Subsequently, both flat belts 12, 12' are advanced forward at equi-speed, and they are conveyed in keeping the panel P held intact. At this time, two turning rollers 14, 14' guide the progress of these flat belts 12, 12' while they hold the panel P sufficient enough. In addition, since both lower end flanges 14a, 14'a of these turning rollers 14, 14' stop a lower edge part of the panel P, even if this panel P is so heavy in weight, it is surely conveyable in this way.