PURPOSE: To make it possible to display a plurality of quantity levels including mixed colors to an observer with intense impression, by rotating a display device at a specified speed, sequentially lighting LEDs in correspondence with the quantity of information, and displaying the quantity level by the size of a light ring formed by the LEDs.

CONSTITUTION: The length of the radius of a rotary display device 1 is equally divided into 8 parts so that the distance from the center has the equally divided interval, respectively. The device is further divided in 7 directions. An LED3 is fixed to each equally divided point. Power is supplied to a common wiring of a rotary shaft 2 and a concentric circle shaped contact point 4 at the back surface, and the LEDs 3 are lighted. In this case, a driving element 7 rotates a motor 5. Then, the LEDs 3 are sequentially lighted from the LED at the central part in correspondence with the magnitude of the output signal of a power amplifier. In this way, a light ring, which corresponds to the magnitude of the signal and the like, is formed for an observer. When the magnitude of the signal and the like is the maximum 7-fold light rings, whose radius is 7/8 the size of the display device 1, are formed.