Trackball device comprising a trackball and a device for adjusting the braking force of the trackball, characterized in that said adjusting device comprises: - a rotating ring in the form of a straight circular hollow cylinder having an inner diameter greater than that of the ball, said ring being topped by a flexible annular braking seal, having an inner diameter less than that of the ball, the seal resting on the ball, the outer periphery of the cylinder comprising: - a first oblong inclined by an angle of a few degrees in relation to the base of the cylinder; - a first plurality of identical notches at right angles to said base of the cylinder, the inner diameter of the hollow cylinder having a diameter greater than that of the trackball and the inner diameter of the annular seal being less than that of the trackball; - a fixed support of said trackball comprising: - a circular void with a diameter equal to that of the outer periphery of the cylinder, the ball being mounted in this void; - a fixed pin and an indexing finger arranged so that, the ring being mounted in the void of the fixed support, the fixed pin is housed in the oblong of the ring and the indexing finger in one of the notches of the ring, the rotation of the ring causing the displacement of the pin in the oblong, the indexed notch to change and a translational motion of the ring parallel to the axis of revolution of the cylinder. - a rotating ring in the form of a straight circular hollow cylinder having an inner diameter greater than that of the ball, said ring being topped by a flexible annular braking seal, having an inner diameter less than that of the ball, the seal resting on the ball, the outer periphery of the cylinder comprising: - a first oblong inclined by an angle of a few degrees in relation to the base of the cylinder; - a first plurality of identical notches at right angles to said base of the cylinder, the inner diameter of the hollow cylinder having a diameter greater than that of the trackball and the inner diameter of the annular seal being less than that of the trackball; - a fixed support of said trackball comprising: - a circular void with a diameter equal to that of the outer periphery of the cylinder, the ball being mounted in this void; - a fixed pin and an indexing finger arranged so that, the ring being mounted in the void of the fixed support, the fixed pin is housed in the oblong of the ring and the indexing finger in one of the notches of the ring, the rotation of the ring causing the displacement of the pin in the oblong, the indexed notch to change and a translational motion of the ring parallel to the axis of revolution of the cylinder. - a first oblong inclined by an angle of a few degrees in relation to the base of the cylinder; - a first plurality of identical notches at right angles to said base of the cylinder, the inner diameter of the hollow cylinder having a diameter greater than that of the trackball and the inner diameter of the annular seal being less than that of the trackball; - a fixed support of said trackball comprising: - a circular void with a diameter equal to that of the outer periphery of the cylinder, the ball being mounted in this void; - a fixed pin and an indexing finger arranged so that, the ring being mounted in the void of the fixed support, the fixed pin is housed in the oblong of the ring and the indexing finger in one of the notches of the ring, the rotation of the ring causing the displacement of the pin in the oblong, the indexed notch to change and a translational motion of the ring parallel to the axis of revolution of the cylinder. - a circular void with a diameter equal to that of the outer periphery of the cylinder, the ball being mounted in this void; - a fixed pin and an indexing finger arranged so that, the ring being mounted in the void of the fixed support, the fixed pin is housed in the oblong of the ring and the indexing finger in one of the notches of the ring, the rotation of the ring causing the displacement of the pin in the oblong, the indexed notch to change and a translational motion of the ring parallel to the axis of revolution of the cylinder.