To improve the stability and workability of a working machine while ensuring the safety of a worker and perform large bore rock mass drilling efficiently.

A casing 9 is rotatably suspended and supported to a hook 7 of a crawler crane 4 travelable on an entering frame 3, and vertical impact force is imparted to a hammer 10 at the lower end of the casing 9. A catch fork outer cylinder is fitted in a rising/falling state to a body of the crawler crane 4. A catch fork inner cylinder 13 is fitted in an expandable state to the catch fork outer cylinder, and a placing base 14 is fitted in a rising/falling state to the tip of the catch fork inner cylinder 13. The lower part of the casing 9 is supported on the placing base 14, and a hollow rotary table machine 20 for imparting axial rotary motion to the casing 9 is placed on the placing base 14.