To prevent damage of connection pipes by avoiding interference with a part in a chassis frame of the connection pipes connected to a trailer side from a tractor side.

The semi-trailer connection vehicle is provided by connecting the connection pipes 5 laid to the vehicle rear via the inside of the chassis frame 3 from a cab back face of a tractor 1, to a front part of a trailer towed by being connected to the tractor 1 via a coupler 4, by folding back to the vehicle front by extracting on the chassis frame 3 on this side of the coupler 4, and comprises a bracket 8 to be insulated from the part in the chassis frame 3 by running the connection pipes 5 on a position for extracting the connection pipes 5 on this side of the coupler 4 in the chassis frame 3 of the tractor 1.