Provided is a capacitor such that the capacity thereof can be made greater compared to a case of simply using only a solid electrolyte as a dielectric body of a capacitor. The capacitor (1) is provided with a solid electrolyte body (3), and a plurality of electrodes (5 and 7) which are formed on the solid electrolyte body (3) and are disposed so as to face each other across the solid electrolyte body (3). The solid electrolyte body (3) has an oxide-based lithium ion conductive solid electrolyte as a base material, and includes oxide particles comprising a portion of the elements configuring the base material.
