Abstract: The invention concerns the construction of optical instruments. The instrument stand allows the instrument to be oriented along three converging axes, and to be held sufficiently firmly in the chosen position. The stand comprises a head which rotates round the first of the three axes of rotation. The head comprises two tracks of overall cylindrical form, the common axis of revolution of which constitutes the second axis of rotation of the instrument; the head also contains two runners which can move along the tracks, and each runner comprises a shaft which can rotate, with friction contact, on its axis. The instrument is fixed to two shafts, which share the same axis, this axis constituting the third axis of rotation of the instrument.The invention also concerns application of such devices to a stand for measuring instruments used in making spectacles.