A liquid-crystal display device is provided which is improved in image quality by supplying a reference voltage signal to a liquid-crystal display panel through a multiplicity of distributed supply paths. The liquid-crystal display device includes a liquid-crystal display panel and a semiconductor device connected to a part of a periphery of the liquid-crystal display panel. The liquid-crystal display panel has a plurality of signal lines for supplying various signals to address pixels, on one of a pair of substrates arranged oppositely through a liquid crystal. The signal lines include a common bus line for supplying a reference voltage signal. The semiconductor device is structured with a semiconductor chip mounted on a flexible board. The flexible board at least has a line leading to a terminal for supplying a signal to the signal line of the liquid-crystal display panel through the semiconductor chip. The reference voltage signal is to be supplied to the common bus line of the liquid-crystal display panel through at least a common line formed on the flexible board of the semiconductor device. The common line on the flexible board is formed in an area outside a mount area of the semiconductor chip and in an area passing through the mount area of the semiconductor chip.