To contrive not to interrupt a work for fixing a rod, and to prevent the danger of falling of the rod by installing two rod fixing means for a boring machine and automatically fixing and operating the rod fixing means alternately by a control means.

The boring machine 1 is composed of a device body 2 and an auto feed device 3, and the main body 2 is operated by manual levers 14. An L-shaped frame 4 is mounted on the auto feed device 3, and the lower end of a hydraulic cylinder 5 is connected. A movable plate 6 is connected to the frame 4 vertically movably, the hydraulic cylinder 5 and a swivel head 7 are joined with the movable plate 6, and the swivel head 7 can be shifted vertically together with the movable plate by working the hydraulic cylinder. The hydraulic chuck of a first fixing means for a rod 8 is conjoined into the swivel head 7 and a hydraulic holder 9 as a second fixing means with the frame. The hydraulic shuck and the hydraulic holder 9 are operated alternately and automatically with the lifting and lowering of the hydraulic cylinder 5, and the rod 8 is forwarded continuously into a ground.