Theoretical calculations have predicted that the band gap of boron carbonitride (BCN) nanotubes can be tailored over a wide range by chemical composition rather than by geometrical structure. The following attempts toward the fabrication of BCN nanotube devices should be of great importance both to further understand their electronic properties and to develop their prospective applications for nanoscale electronic and photonic devices. Here, the direct synthesis of massive BCN/C nanotube junctions has been realized via a bias-assisted hot-filament chemical vapor deposition method. The electrical transport measurements of individual nanotube junctions were performed on a conductive atomic force microscopy. It is found that the BCN/C nanotube junction shows a typical rectifying diode behavior.