To prevent a wire rope for suspending a kelly-bar from making contact with a support frame when moving a leader between a raised attitude and a horizontal attitude.

A roller device 44 having guide roller 48 and 53 is provided on the cylinder support part 43 of the support frame 41, so that a main winding rope 28 and an auxiliary winding rope 29 make contact with the guide roller 53 and the guide roller 48, respectively when the leader 10 is moved from the raised attitude to the horizontal attitude. Accordingly, when the main winding rope 28 and the auxiliary winding rope 29 are wound in the state where the leader 10 is laid in the horizontal attitude, the ropes 28 and 29 are smoothly moved toward a main winding winch 7 and an auxiliary winding winch 8 by the guide rollers 53 and 48 without being rubbed with the cylinder support part 43 of the support frame 41.