PURPOSE: To facilitate the loading and unloading of cargo and prevent the cargo from dropping down from the tail gate when the tail gate is vertically moved, by providing a cargo moving unit such as a roller at the cargo placing side of the tail gate so that the cargo moving unit can be move in and out.

CONSTITUTION: The tail gate A is vertically moved by a parallel link mechanism B between the ground and a bed 1 while the tail gate remains horizontal. The cargo placing side 3 is bent, thereby forming a U-rail 4. An air tube 5 is provided over the length of the rail 4. A frame 6 pivoted with a roller 7 is installed over the air tube 5. Compressed air is supplied from a pipe 8 to the air tube 7 to vertically move the roller 7 with the frame 6 into and out of the cargo placing side 3. When the tail gate A is vertically moved, the roller 7 is put in the rail 4 to prevent the cargo 15 from moving.