Abstract: The machine includes a frame on which is suspended on a shaft a support for two inclined cutters. The support includes slots of different inclination in which are mounted guide rollers connected to housings in which inclined cutters are rotatively mounted. A jack shifts the housings and consequently adjusts the inclination of the cutters. An additional cutter is located in front of the inclined cutters and is adapted to effect a rough cutting of the trench. A smoothing shoe is openable to a variable extent with the inclination of the cutters.