Abstract: A cargo transporting box body with a cargo-handling device for cargo unloading or loading, the box body having on its bottom a floor board movable, and a movable partition wall on the floor board such that, when the movable partition wall is latched, only the floor board is movable, and when allowed to move, the movable partition wall moves in association with the floor board. A sprocket is attached around an axis at the base of the movable partition wall and driven by a reversible motor. A first chain has one end fixed to the posterior end of the of the box body and the other end to the anterior end; while a second chain has one end fixed to the posterior end of the box body and the other side the anterior end, and the first and second chains cross with each other at their mid-portions and engage with the sprocket.