A thin-film device incorporates: a substrate; an insulating layer, a lower conductor layer, a dielectric film, an insulating layer, an upper conductor layer and a protection film that are stacked in this order on the substrate; and four terminal electrodes. The four terminal electrodes touch part of end faces of the upper conductor layer, and part of the top surface of the upper conductor layer contiguous to the end faces. The protection film has four concave portions, each of which has a shape that is recessed inward from the edge of the protection film except portions thereof corresponding to these concave portions. The four concave portions expose respective portions of the top surface of the upper conductor layer that touch the four terminal electrodes. The four concave portions accommodate respective portions of the four terminal electrodes.