One example of this bone drill reamer is a reamer 1 which is provided with a drill section 2 and a shaft 3. A main body 19 of the shaft 3 has no slit formed on the outer circumferential surface thereof and bends in response to an external force due to the elasticity of a material thereof. The drill section 2 comprises a cutting edge section 4 and a tubular cutting edge-side connection section 5 integrally joined to the cutting edge section 4. The cutting edge-side connection section 5 is provided with projections 10 on the inner circumferential surface in the vicinity of an opening of a cutting edge section through hole 6. The projections 10 mate with a spiral groove formed on the shaft 3.
