PURPOSE: To offset difference in tension generated in and out of the curved part of a conveyor belt, prevent deviation at a belt edge part, and drive said belt smoothly by tilting said edge part in a direction opposite to the side on which a conveyor is curved facing the direction in which said belt advances.

CONSTITUTION: When a conveyor belt 3 is curved leftward facing the direction in which it advances, both edge parts 4, 4 of the cylindrical conveyor are tilted to the right side, i.e., outwardly in relation to the center of curvature radius. And, a shape retaining roller positioned on the right side is omitted, to generate tension inside the conveyor belt 3. Thereby, the inner compression and the outer tensile force, which are generated due to the curving of the conveyor are just offset, making the tension of the whole belt uniform, preventing deviation at the edge part 4, and enabling smooth driving of the belt.