To provide a structure of a belt for reducing run-off of a carried object through a gap even in a state in which the gap between a surface of the belt and a lower surface of a side guard is fluctuated.

A raising part 1 is endlessly provided on widthwise both end parts of a flat belt 2 to prevent the carried object slipping through the gap 10 from slipping sideways even when the belt is lowered between carrier rollers and the gap between the belt and the side guard is increased. Although the size of the diameter of a belt pulley may constrain the height of the raising part, providing of a slit is to the raising part relaxes rigidity due to the belt structure to overcome this problem. Accordingly side slipping/dropping of the carried object is prevented by providing the raising part on both edge parts widthwise of the belt.