PURPOSE: To enable the vertical adjustment of the position where a culvert is formed, while a machine body is advanced, by providing a device for adjusting vertical direction between a holder and a vertical edge.

CONSTITUTION: When the work for making the culvert is performed by the subsoiler 5, the rotational force of a PTO shaft is transmitted to a vibrating arm 14 through the intermediary of a transmission shaft 15, an eccentric cam 16 and a vibration-transmitting arm 17 to vibrate the vibrating arm 14 and thereby the vertical edge 10 is vibrated in the longitudinal direction. A tractor 1 for agricultural use is advanced, a top link 3 and lower links 4, 4 are rotated downward, a supporting wheel 20 is made to touch the ground and, while the projected edge body 10a of the vertical edge 10 is advanced in a certain depth in the earth, the culvert is formed by a cylindrical body 21. By operating a control valve, a hydraulic cylinder 11 and a hydraulic piston 12 are adjusted elastically, and thus the vertical adjustment of the culvert can be performed, while the tractor 1 is advanced.