A cargo transportation box body with a cargo-handling device, used for cargo loading and unloading. The box body has on its bottom portion a floor board that is movable by a cylinder. A movable partition wall is provided on the floor board. When the partition wall is latched, only the floor board moves, and the wall moves with the floor board when necessary. The movement of the forwardly and backwardly movable floor board and of the movable partition wall that moves synchronously with the floor board or moves relative to the floor body are selectable. Further, the movable partition wall is prevented from swinging to the left and right, so that the wall can be maintained in a stable condition. A sprocket (3) is provided at a foundation portion of a movable partition wall (12) so as to be rotated by a reversible motor (47). The sprocket (3) has projections on the periphery that engage with ring body holes of chains (2a, 2b). A first chain (2a) and a second chain (2b) are arranged in a crossing manner. One end of the first chain (2a) is fixed to the rear end side of a box body (10), and the other end to the front end side. Further, one end of the second chain (2b) is fixed to the front end side of the box body (10), and the other end to the rear end side. Intermediate portions of the chains (2a, 2b) are engaged with the sprocket (3).