To facilitate disassembly and assembly without any deterioration in boring performance so as to improve portability by comprising freely attachable/detachable skid units, which can be freely attached/detached to/from specific end parts of a plurality of guide frame units parallel to the boring direction, and a drill unit giving longitudinal propelling force to a drill rod.

A rear skid unit RSU is arranged freely removably in the boring directional rear end part between two guide frame units GFU arranged parallelly to the boring direction at a certain interval, and a front skid unit FSU is arranged freely removably in the boring directional front end part between the guide frame units GFU. A drill unit DU giving longitudinal propelling force to a drill rod 7 is supported between the guide frame units GFU so as to be freely moved longitudinally in the boring direction along the guide frame units GFU. Assembly of the respective units GFU, RSU, FSU, and DU into a drill machine and disassembly from the drill machine into the respective units GFU, RSU, FSU, and DU can be freely carried out.