PURPOSE: To display a multi-signal different in a clock frequency and a synchronizing frequency by finding ratios of picture elements of an input signal and an LCD panel, and writing them simultaneously in vertical and horizontal drivers according to these ratios.

CONSTITUTION: An input signal process circuit 9 performes signal processing to project an image clearly on an LCD panel 12 by a signal from an input signal switching circuit 13. Here, an input signal discriminating circuit 7 discriminates a classification (for example, an NTSC TV signal, a personal computer signal or the like) of an input signal, and a timing controller 8 calculates ratios (m and n) of the vertical and horizontal picture element number of the input signal and the vertical and horizontal picture element number of the LCD panel 12, and sends out signals by (m) pieces to a vertical driver 10 to be written simultaneously by (n) pieces in a horizontal driver 11. Thereby, since a multi-signal different in a clock frequency and a synchronizing frequency can be displayed by a single LCD monitor, a multi-think monitor making the most of characteristics such as a thin type or low voltage can be realized.