The present invention provides a liquid crystal display device, which includes a liquid crystal display panel (2) and a backlight module (1) arranged on an undersurface of the liquid crystal display panel (2). A first flexible circuit board (20) and a second flexible circuit board (15) are electrically connected together and height-constraint components (22) of a liquid crystal display panel drive circuit and a backlight source drive circuit are collectively arranged on the second flexible circuit board (15). A mold frame (11) of the backlight module (2) is provided with accommodation holes (111) formed therein to receive and accommodates the height-constraint components (22) so as to effectively reduce the thickness of the liquid crystal display device and improve product competition power.