A method for producing a thin oxidized carbon film according to the present disclosure includes: a first step of preparing a thin carbon film and a copper oxide being in contact with the thin carbon film and containing a mixture of Cu2O and CuO; and a second step of applying a voltage or a current between the thin carbon film and the copper oxide, with an electrical potential of the thin carbon film being positive relative to that of the copper oxide, and thereby oxidizing and converting a contact area of the thin carbon film with the copper oxide into an oxidized portion composed of oxidized carbon so as to form a thin oxidized carbon film having the oxidized portion.