PURPOSE: To dispense with a holding platform for the expansion conveyor by providing an expansion guide frame on an inclined conveyor which contains a horizontal expansion conveyor.

CONSTITUTION: When a sliding belt conveyor 16 is pulled out through the lower side of an inclined belt conveyor 13 onto a bed 22 of a truck 21, a tail part of the sliding belt conveyor 16 is moved up aslant along a guide frame 14 at the tail part, and a head part is moved horizontally with the tip part 15a of an expansion guide frame 15 at the head part. Thus, the sliding belt conveyor 16 can be installed without need of any particular holding platform. Besides, when the sliding belt conveyor 16 is moved, through the head between the upper end part of the inclined belt conveyor 13 and the conveying side of the sliding belt conveyor 16, the head can be covered by expanding and contracting an expansion chute 17.