Abstract: A stand apparatus for supporting a medical instrument such as ophthalmic instrument. The apparatus comprises a vertically movable arm, a guide rail for guiding the arm for vertical movement, a rod extending in parallel with the guide rail, and a braking device provided on the base portion of the arm and selectively engageable with the rod. The braking device includes; at least one braking member having at least two biting edges spaced from each other by a distance slightly greater than the diameter of the rod so as to bite the outer surface of the rod, the braking member swingably engaging at its one end with the base portion of the arm; a resilient spring for normally pressing the biting edges of the braking member into engagement with the outer surface of the braking member; a sliding arm member adapted to be moved by a brake releasing device in the direction perpendicular to the rod; and a link arm member to which the slide arm member and the other end of the braking member are connected pivotably.