A supporting mechanism of a micro gravity rotating apparatus in which magnetic bearings are applied to the rotary shaft in order to absorb and damp vibration of the rotary shaft. A casing (10) is provided with recesses (10a, 10b), coils (1, 2) of magnetic bearings (11, 12) are arranged on the periphery thereof and vibration sensors (3, 4) are arranged on the inside thereof. Lower end of a rotary shaft (30) is coupled with a motor (13), opposite end parts of the rotary shaft are supported by magnetic force, four arms (24 to 27) are secured on the X and Y axes in the horizontal direction and experiment boxes (20 to 23) are fixed to the forward ends thereof. Experiments are conducted by placing plants, animals, or the like, in the boxes (20 to 23) and then turning the boxes (20 to 23) in the space. The rotary shaft (30) vibrates due to unbalance of objects in the boxes and the vibration is detected by means of the vibration sensors (3, 4) and absorbed by controlling the exciting current of the coils (1, 2).