A rotating tool for cutting microtrenches (1) comprising a disk-like rotatable body (2) having a central axis (X) and adapted to be secured to an arriver spindle of a digging machine or the like and a circular peripheral edge (3), at least one first trenching peak (5) designed to engrave a rigid substrate for cutting a microtrench, which is secured to the circular peripheral edge (3) in an at least partially radial position with a predetermined maximum width (h). The tool (1) also comprises a second trenching peak (7) other than the first peak (5), whose maximum width (l2) is smaller than that of the latter. The second peak (7) is secured to the peripheral edge (3) in an angularly staggered position relative to the first peak (5).