PURPOSE:To reduce the impedance of a reference voltage wiring connected to output stage circuits and facilitate avoiding misoperation of input stage circuits caused by potential fluctuation by a method wherein the reference voltage wiring connected to the output stage circuits is composed of a conductive layer which covers almost the whole region of internal circuits. CONSTITUTION: A reference voltage wiring 17 is formed two-dimensionally so as to cover almost the whole region of the center part, i.e. internal circuits, of a semiconductor integrated circuit device 1 and connected to output stage circuits 4. Thus, by composing the wiring 17 connected to the output stage circuits of a conductive layer, for instance an aluminum film, the resistance of the wiring 17 can be reduced significantly and the impedance can be reduced. Therefore, the potential fluctuation which is induced when a plurality of the output stage circuits 4 are operated simultaneously can be substantially attenuated. As the potential fluctuation transmitted to a reference voltage wiring 2c can be reduced, the misoperation of input stage circuits 3 can be avoided and the electrical reliability of the semiconductor integrated circuit device 1 can be improved.