The present invention concerns an endless conveyor belt for a conveyor device, which conveyor belt comprises a belt body that can be transversely deformed between a flat configuration, at rest, and a tubular configuration. This belt body comprises two transition regions over its width which between them define a central belt portion, as well as two side belt portions situated between each of them and the nearby side edge. At least one thickness of the side belt portions is greater than at least one thickness of the central belt portion, forming at least one over thickness region on each of the side belt portions.