The utility model discloses a circular chambering device for a pre-drilling type side pressure test. The circular chambering device comprises a chambering part, a drill rod and a drill bit part, the reaming part and the drill rod part are both cylindrical, and the outer diameter of the reaming part is larger than that of the drill rod part. The reaming part is coaxially welded to one end face of the drill rod. The drill bit part is cylindrical, and the outer diameter of the drill bit is consistent with the outer diameter of the drill rod; a threaded hole is formed in the end face of the tail end of the drill bit, a threaded rod is coaxially arranged on the end face, not connected with the reaming part, of the drill rod, and the threaded rod is screwed in the threaded hole. During use, wherein the drill bit part and the drill rod are arranged on the drill rod. And meanwhile, the gaps among the drill bit, the drill rod and the hole wall are increased, so that the acting force of upward-returning slurry on the hole wall is reduced, and therefore, the drill bit has the advantages that the damage to the hole wall can be reduced, the hole forming quality is improved, the hole drilling and forming cost is reduced, the production efficiency is improved, the disassembly and assembly are simple and quick, and the drill bit is suitable for various types of drilling machines.