PURPOSE: To shorten the stroke of a freight unloading plate provided in a freight body of a freight truck by reducing the initial freight unloading weight of the plate by moving the freight body backwardly by first telescopic cylinder to then unload the freight at the rear in the freight body and operating the plate in the freight body to unload the residual freight from the freight body.

CONSTITUTION: The freight body 2 of a freight truck is moved on guide rails 5 of a truck body frame 1, and formed with an opening 7 over the entire width at the rear of the floor plate 6 thereof. A bottom plate 9 is fixed to the rear of the frame 1. When the freight body 2 is disposed at the movable position, the opening 7 is covered by the bottom plate 9. When unloading the freight from the freight body 2, the freight body 2 is moved backwardly by the retraction of the rod from a cylinder C1 to thereby open externally the opening 7 and to then unload the freight at the rear in the freight body 2. A freight unloading plate 12 is moved backwardly by the retraction of the rod from a cylinder C2 to then unload the freight through the opening 7 out of the body 2.