Abstract: A rock drill guide tool comprises a sleeve arrangement (8) placed around a tubular drill tube (9) which rotates during a drilling operation and through which drilling liquid is supplied under pressure during drilling intervals. The sleeve arrangement includes a plurality of support units (15, 16) which can be projected out into contact with the wall of a drill hole and which are placed circularly in the sleeve arrangement. The support units (15, 16) are placed in at least two ring sections of the sleeve arrangement and are provided with elements (19, 20) which project out against the wall of a drill hole. These elements engage the rock so as to cut grooves into the wall of a drill hole as the drill is moved down during a drilling operation.