To obtain a crushing device for crushing a hard subsoil with light vibration and light noises by means of a drill and the crushing device.

A crushing device is so constituted that a drill shaft 5 is extended from a drill driving source 4, a cutting edge 6 is loaded to the front end of the drill shaft 5, at the same time, a hydraulic jack main body 7 is loaded to the drill shaft 5 at the lower part of the split driving source 4 and that the crushing device consisting of split type inside wedges 9a and 9b having tapered thickness toward the front end and outside wedges 10a and 10b broadening the thickness toward the front end to the outside of the inside wedges 9a and 9b is provided in the front end of a hydraulic cylinder 8 of the hydraulic jack main body 7. In that case, after a hole having the approximately same diameter as that of the crushing device is bored in a hard subsoil with a rotational drill 3, the hydraulic cylinder 8 of the hydraulic jack main body 7 is lowered, and after the crushing device is inserted into the bored hole, the inside wedges 9a and 9b are widened by pushing the hydraulic cylinder 8 into them to make a crack into the hard subsoil.