Development of the integrated circuits for 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 at Kenkyu Seika Katsuyou Plaza Hiroshima October 2002. The electrical power consumption for lighting the road sign with white light emitting diode (LED) using the block duty circuit was become low down to about 3 W, and this value is 1/3 compared with static operation. As a result of use the block duty circuit, the size of solar cell become 1/3, and the capacity of battery become 1/2.