An object is to prevent a defective indication caused by a reverse twisted domain generated from the dummy pixel region which is provided in the periphery of a display pixel region. By setting a signal voltage to be applied to the pixels of the dummy pixel region to be lower than the maximum value of a video signal voltage which is applied to the display pixel region and also setting it to be in a level by which a defective indication is not caused due to a traverse electric field between the neighboring dummy pixel region and the display pixel region, generation of the reverse twisted domain within the dummy pixel region can be suppressed. Thereby, the defective indication caused by the reverse twist can be prevented.