Various kinds of finishing and hardening treatments of holes by methods of plastic surface deformation can find application in many branches of engineering industry. In particular for burnishing holes on a milling or drilling machine tool. A device for diamond-burnishing of holes increases the functional possibilities, improves the quality of the treated hole surface and the endurance of the burnishing tool, provides the opportunity for a precise regulation in order to get the necessary hole caliber, and uses the load of all the weights for obtaining the necessary pressing force. The device structure comprises a housing with a tapered stem, central and terminal arms with crossheads and shafts, bars with weights, a foot with a cylindrical body, and an arbor with a diamond-burnishing tool.