Screen brightness is improved in an IPS type liquid crystal display device.A common electrode having a slit is disposed over a rectangular pixel electrode with an insulating film attached therebetween. The slit has a linear part and a bend part. The bend part is necessary for preventing pressing domain. The transmittance in the bend part is increased by making the thickness of the insulating film below the bend part of the slit to less than the thickness of the insulating film at the linear part of the slit, thereby increasing the transmittance of the entire pixel. Thus, the screen brightness can be improved.