PURPOSE: To improve the followability of a cover belt by pivotally supporting cover belt front/rear support rollers at the angle change section and a conveyor belt surface guide roller to link plates and connecting and supporting the link plates between cover belt pulleys.

CONSTITUTION: Lower stab guide rollers 19 pivotally supported by individual link plates 12 are rotated in contact with the surface of a belt conveyor 1 at the angle change section, and a long guide roller 17 is rotated in contact with the outside rear face of the cover belt 7 respectively. The cover belt 7 is advanced at the fixed and minimum distance from tops of the center stile 2 and ear stiles 3 of a conveyor belt 1 without being brought into contact with them. Accordingly, the followability of the cover belt is improved.