In a belt unloader provided with a vertical carrier (53) for carrying bulk cargo vertically, a screw feeder system is supported by a supporting frame (14) connected to a body frame (18) such that the supporting frame is allowed to be tilted. The screw feeder system is provided with a screw propeller (2) rotated about the center of a shaft extending in the vertical direction for taking bulk cargo in, a loading orifice (23) opposite to the upper part of the screw propeller, and a releasing plate (13) disposed at the upper end of the screw propeller for releasing bulk cargo from the screw propeller toward the loading orifice. The bulk cargo taken in through the loading orifice is carried vertically with the bulk held between a descending belt (20) and an ascending belt (21).