Cylindrical deep hole boring device with auxiliary support

The utility model relates to a device for machining a cylindrical hole, in particular to a cylindrical deep hole boring device with an auxiliary support. The cylindrical deep hole boring device with the auxiliary support solves the problems that machined surface can be scratched when a tool retreated in a machining process of an existing cylindrical hole machining device, and when the hole is deep, a boring rod deforms seriously, and errors of the shape and the position of a bored hole are big. The cylindrical deep hole boring device with the auxiliary support comprises a boring rod and a boring tool, holes are arranged in axial center and the radial direction of the boring rod, the boring tool is arranged inside the radial hole of the boring rod, and a double-cone core bar is arranged inside the axial hole of the boring rod. Two cone bodies are arranged at the front end of the double-cone core bar, and the conical degrees of the two conical surfaces of the cone bodies are identical. A floating support is fur