A coin-type electrochemical element enables the external lead terminal portions to be accurately and reliably attached to a first lid portion and to a second lid portion of the coin-type electrochemical element, and a method of its production. A coin-type electric double layer capacitor includes a first lid portion and a second lid portion. External lead terminal portions, each having a nearly triangular shape, are separately connected to the outer surfaces of the lid portions. Upon providing the external lead terminal portions having the triangular shape, a welded portion is allowed to have an increased area enabling the coin-type electrochemical element of even a small size to be accurately and reliably welded and making it possible to provide the coin-type electrochemical element having excellent reliability.