Abstract: The invention concerns a device for positioning a surgical instrument, characterized in that it comprises a fixed support combined with at least: a first mobile element articulated on the fixed support about a first axis substantially parallel to the plane wherein the patient is placed and capable of carrying out a first movement; a second mobile element articulated at the end of the first element about a second axis substantially parallel to the plane wherein the patient is placed and capable of carrying out a second movement; a deformable element fixed on one side to the end of the second mobile element and capable of carrying out a third rotating movement about a third axis; a prehensile member fixed on the side opposite to that of the second element to the deformable element; a device for locking a surgical instrument on the prehensile member; and actuating means for producing the rotating movements about the different axes.