To provide a representative light device with which a representative lighting in a bath tab is easily enjoyed with no large-scale wiring construction required.

A representative lighting device 2 comprises a case 3 of a closed structure which floats on a water surface W in a bath tab or submerges under water, a light emitting part 4 provided at a position under the water surface W of the case 3, a battery 8 provided in the case 3 which supplies an electric power to the light emitting part 4, and an operation switch 9a where the light emission of an LED7 is operated from outside the case 3.