Earth boring device

An earth boring device for making substantially horizontal bores, said device comprising a boring head (14) rotatable about an axis (16) fixed relative to and extending longitudinally of said head, said boring head being elongated along said axis and having a front end and a rear end, said boring head at said front end having a tip and a control surface which control surface is arranged at an incline to said axis and extends rearwardly from said tip for control of the direction of said head, and said boring head having a cylindrical outer surface of substantially uniform diameter extending forwardly from said rear end of said head into intersection with said control surface and tip to define a point along said axis of rearmost extent of said control surface, and at least one jet (20) carried by said head for the discharge of a pressurized boring fluid from said head, the openings of said jets being arranged on a given side of said boring head (14) parallel to said axis (16) and facing away from said control surface (18), said jets being located rearwardly of said rearmost extent of said control surface and having stream directions inclined to said boring head axis (16) so that the streams flowing from the jets reach essentially only the region of earth lying next to said given side of the boring head.