To easily perform center alignment of a drill rod when the drill rod for rock drill is added and recovered.

An arm 12 provided with a rod clamp 11 gripping a drill rod 9 is pivotally supported on a base 13 provided on a side of a guide shell 2, and the drill rod 9 is moved from an evacuation position onto axial line X of a hole to be drilled due to the turn of the arm 12. In this case, the base 13 is slidably supported on a support plate 15, and a slide cylinder 18 moving the base 13 in the direction in which it crosses the direction of travel of the drill rod 9 due to the turn of the arm 12 is provided.