A display device is provided in which contact holes, each having a sidewall with an ideal tapered shape, are formed in a structure in which a silicon oxide film, a silicon nitride film and a silicon oxide film are stacked in the named order. The display device includes a first silicon oxide film, a silicon nitride film stacked on the first silicon oxide film, a second silicon oxide film stacked on the silicon nitride film, and a contact hole which extends through at least these three layers. In the display device, letting d2 and d3 denote, respectively, a film thickness of the silicon nitride film and a film thickness of the second silicon oxide film, these films are stacked to satisfy the relationship d2