An input device includes a universal serial bus interface, a white light-emitting diode unit, a red light-emitting diode unit, a green light-emitting diode unit, a blue light-emitting diode unit and a driving part. The driving part receives electricity through the universal serial bus and drives at least one of the white light-emitting diode unit, the red light-emitting diode unit, the green light-emitting diode unit and the blue light-emitting diode unit to emit a light beam. Consequently, the light beam with a higher luminous intensity and a specified color is outputted from the input device.