A rotation output device including a lock mechanism for automatically locking an output shaft without inertia or a need to pivot the output shaft by the operator after the input shaft stops rotating. The rotation output device includes an output gear for inputting a rotation driving force; a lock ring restricted from rotating; output rings for rotating integrally with the spindle; a click spring for rotating the output rings with respect to the output gear; float gears which are held by the output ring to be urged radially outward and are fixedly engageable with the lock ring; and central pin insertion through-holes and side pin insertion through-holes provided in the output rings for releasing the float gears radially outward and fixedly engaging the float gears with the lock ring. The click spring relatively rotates the output rings by the stoppage of the rotation driving of the output gear.