PURPOSE: To constitute the rotary chair so that its seat part can be rotated, stopped and fixed satisfactorily against a base by a driving mechanism, and also, can be rotated easily manually.

CONSTITUTION: In the inside periphery of an supporting frame 52 fixed to a base 3, a timing belt 53 is arranged and fixed annularly. On a supporting plate 54 being freely rotatable against the base 3, a motor 56 is set, and a gear 58 rotated by this motor 56 is engaged with the timing belt 53. A brake pad being freely pressable against the timing belt 53 is attached on the supporting plate 54 side.