To attract a passerby's interest, curiosity or the like by applying the constitution that the rotation of a rotary base is smoothed via a reaction force as a force for rotating a reaction wheel, and a top is made to move on a floor slowly and stably in such a state as intermittently supported on a play support wheel, upon the acceleration and vigorotus rotation of the rotation base.

When an autorotation top is placed on a floor, the cap member 12 of a vertical axis 2 and a free rotation support wheel 3 come in contact with the floor for supporting a rotation base 1. Thereafter, when a solar battery 6 is exposed to sunlight and a reaction wheel 5 is rotated on the operation of a motor 4, a reaction force from the reaction wheel 5 is sent to the rotary base 1 via the motor 4, and the base 1 rotates along a direction opposite to the reaction wheel 5. The rotation of the reaction wheel 5 is retarded, due to the air resistance of vanes 22 and 22 attached thereto, but a reaction force sent to the rotation base 1 increases correspondingly, thereby ensuring a smooth rotation start. Also, when the rotation base 1 is accelerated and begins to rotate vigorously, the whole of the top moves in such a state as intermittently held on the free rotation support wheel 3, but a stable motion with a slow swing is ensured, because the center of gravity as a whole is at a lower position.