Device for surface mounting and capacitor element

A capacitor element comprising:

• a substantially plate-shaped base having a valve effect;
• a first functional layer including a dielectric oxide film, a solid electrolyte layer, and an electrode layer laminated in that order on a first surface of the base, the first functional layer having an outer circumference;
• a second functional layer including a dielectric oxide film, a solid electrolyte layer, and an electrode layer laminated in that order on a second surface of the base;
• a first insulating layer that covers a circumferential edge of the first functional layer on the first surface;
• a second insulating layer that covers a circumferential edge of the second functional layer on the second surface;
• an electrode portion formed by at least part of the first surface of the base being exposed around an entirety of the outer circumferential side of the first insulating layer, such that the electrode portion extends around an entirety of the first functional layer;
• at least one through-hole that passes through the base;
• and
• a third functional layer provided on an inner circumferential surface of the at least one through-hole that includes a dielectric oxide film, a solid electrolyte layer, and an electrode layer laminated in that order from a side that contacts the base, the electrode layer of the third functional layer electrically connecting the electrode layer of the first functional layer and the electrode layer of the second functional layer,
• wherein the first insulating layer covers the entire circumference of the circumferential edge of the first functional layer and the second insulating layer covers the entire circumference of the circumferential edge of the second functional layer.