Abstract: An apparatus for improving balancing skill which comprises a disk with threaded hole in its center and a threaded rod screwed through the threaded hole. The user stands on the disk and attempts to maintain the disk in a horizontal position, i.e., balance himself on the disk and supported on the rod. Difficulty of maintaining balance is proportional to the distance from the contact point with the floor to the hole in the center of the disk. This distance is indicated for a given position of the rod by indicia imprinted on the side of the rod. The indicia therefore gives the user the opportunity to measure the difficulty of performing the exercise and to vary the difficulty by a controlled increment.