To lengthen the sevice life, simplify maintenance and control, and previously prevent a railroad accident by arranging blue and yellow lamps at a specific rate, and arranging polished glass on a front face of the lamps in order to display a white lamp by using the yellow and the blue lamps of a light emitting diode.

In order to display a white lamp by using yellow lamps 3 and blue lamps 4 of a light emitting diode, the ratio of the blue lamps 4 and the yellow lamps 3 is set at a rate up to 1:3.5 to 1:5.0, and polished glass is arranged on a front face. Since only an electric current half of the yellow lamps can be flowed to the blue lamps, two blue lamps are juxtaposed. When the polished glass 5 is used, the light of an internal electric lamp can be diffused, and colors of blue and yellow are sufficiently mixed, and can be seen as a white lamp even when looked at close range and even when looked from a distance place, and the light is not dispersively looked. Therefore, the service life is lengthened, maintenance and control of a signal lamp can be simplified, safety is enhanced, and a railroad accident can previously be prevented.