A liquid crystal display device for improving working efficiency and reducing manufacturing cost. In the device, a data integrated circuit has a data output group for supplying pixel data to data lines and a dummy data output channel group which is not supplied with pixel data. A channel selector selects an output channel of the data output channel group. A tape carrier package is mounted with the data integrated circuit and has a data output pad group connected to the data output channel group and a dummy output pad group. The pixel data is applied, via the data output channels selected by the channel selector, to the data lines.