A liquid crystal display panel 10A of the invention has gate electrodes G of TFTs, scan lines 16, and auxiliary capacitor electrodes 18a, which are coated with a first insulating film 27 composed of a thick insulating layer 25 and thinned insulating layer 26. A part above the auxiliary capacitor electrodes 18a is coated only with the thinned insulating layer 26, and drain electrodes D are extended on the first insulating film 27, which is not thinned, so as to coat the thinned insulating layer 26. On a second insulating film 28 provided between the pixel electrodes 20 and the drain electrodes D, contact holes 30 are formed at portions above the drain electrodes D on the first insulating film 27, which is not thinned, above the auxiliary capacitor electrodes 18a, and via the contact holes 30, the pixels 20 and the drain electrodes D are electrically coupled to each other. By providing such a constitution, a liquid crystal display device and its manufacturing method can be provided, with only a small number of bright point defects, and with an increased capacitance of the auxiliary capacitor electrodes without a reduction in the aperture ratio of each pixel.