A functional device including on a substrate a first electrode layer, a second electrode layer opposed to the first electrode layer, a functional layer disposed between the first electrode layer and the second electrode layer and a wiring for applying a potential to the first electrode layer or the second electrode layer, wherein there are provided a first insulating layer formed on the second electrode layer in such an arrangement that the side wall of the functional layer is covered and a contact hole formed in the first insulating layer extending to the second electrode layer in which the wiring for connecting the second electrode layer is provided.