PURPOSE: To improve workability and efficiency thereof in a small space, by arranging plural endless conveyers vertically piled up so that each stage can be delivered out in turn and installing an ended chain for delivering out each stage conveyer and a endless chain for driving, in the case of an expansion conveyer for conveying earth for civil engeering work.

CONSTITUTION: A conveyer 10 drives the third motor 21 to drive an ended chain 22, pulls forward a free chain wheel 28 in the rear to shorten the ended chain 22 on the higher stage and an endless chain 24 on the lower stage and also to lengthen a part leading from the lowest stage to the highest stage. By doing this, each stage is delivered out in turn. Next, the fourth motor 23 is started to give a main roller 12 turning motion through the endless chain 24 and a driving chain wheel 25 and to drive a conveyer in the conveying direction. The conveying direction is switched by the normal/reverse run of the motor 23 and the conveyer 10 is returned in the original piled up state by the reverse run of the third motor 21. Owing to this constitution, it is possible to adjust a conveyer's length in a small space and to improve workability and efficiency thereof.