PURPOSE: To enhance the boring ability while such a merit of a hand-held rock drill as capable of turning with a minor radius is well maintainned and to reduce the labor of the operator.

CONSTITUTION: A centrizer 3 to hold the core of a rod 24 of a hand-held rock drill C is installed at the tip of a frame 1 in straight form, and thereby a stand A is formed. A propelling device B is formed by installing fast a bed 10 provided with a retaining member 12 at a guide bridge 11a of a rodless cylinder 11. The hand-held rock drill C should be of a pressurized air drive type or oil-hydraulic drive type, and a grip 22 furnished on the body 21 is retained by the retaining member 12 so that mounting in the suspended state is generated, and also the rod 24 is supported by the centrizer 3. A detaining member 41 detains supporting members 52. 53 fixed to a certain moving device on the side opposite that surface of stand A where the rock drill C is installed. The member 41 is composed of a plate 41a, back-up piece 41b, and screw 41c to press the supporting members.