The present invention provides a liquid crystal display device with high image visibility at low power consumption and produced at low cost by using an interlayer dielectric film, which has low dielectric constant, high heat-resistant property, high optical transmissivity, high film thickness and high flattening property produced at low cost. An organic siloxane dielectric film is used as an interlayer dielectric film of the liquid crystal display device. A ratio of nitrogen content to silicon content (Ni content/Si content) in the interlayer dielectric film is controlled to 0.04 or more in the element ratio. The limiting film thickness to suppress and limit the cracking caused by the thickening of the interlayer dielectric film is set to 1.5 μm or more.