In a conveyor device for conveying sheet material in sheet or web form, two pairs of conveyor rollers are spaced apart with their axes parallel to one another, each pair including a deformable roller cooperating with a substantially non-deformable conveyor roller, and the two pairs of rollers are driven by a non-deformable drive roller which is mounted for rotation about a fixed axis disposed between them, with the deformable conveyor roller of each pair pressed against its cooperating non-deformable conveyor roller and also against the drive roller so that compensating differences of peripheral speed occur at the two pressure nips of each deformable conveyor roller. Each deformable roller is pressed in a direction located in or at least proximate to the plane of the bisector of the dihedral angle between a plane through the axes of the drive roller and the deformable roller and a plane through the axes of the deformable roller and its cooperating non-deformable conveyor roller. As a result, the speed of conveyance by the pairs of rollers is not changed by variations of the pressure applied or of the hardness of the roller surfaces and is practically independent of the diameters of the rollers.