The present invention aims to prevent display luminance difference and burning with a line at which the polarity inversion switches when the order of inversion of black and video changes in the middle of the screen by a frame polarity inversion drive in a liquid crystal display device for performing black insertion drive. An enable signal (VOE) to each gate driver 5A to 5N is independently controlled, a start pulse (VSP) input to write a black signal is performed at an arbitrary timing within one frame period with respect to the gate driver 5A to insert a black image within one frame period, a write polarity of the video signal is inverted in frame cycle with the video display start pulse as a base point, and a write polarity of the black image signal is inverted in frame cycle with the black display start pulse as a base point.