The dental device (10) has a light source (14) e.g. LED which is controlled by a control unit (36). A power source (20) such as an accumulator or a rechargeable battery is connected with double-layer capacitors (26,28). The power source is provided within the housing (12). The power obtained from the power source and double-layer capacitors, is simultaneously supplied to the LED. The double-layer capacitors are interconnected with a voltage and current equalization circuit. The light rays having irradiance of 4000-20000 mW/cm 2>；, are emitted from the LED.
