Development of road sign illuminated by using the white light emitting diode with the solar cell was demonstrated. This road sign was consisted of the solar cell, road sign，controller，and the battery and was installed along the National Road 2 on middle of March 1999. After installation of this road sign，this road sign was illuminated from sundown to sunrise without supplying the commercial electric power. Since this road sign illuminated by using the white light emitting diode with the solar cell was able to install without the commercial electric power，this system was one of the most promising road sign system in the future.