The present invention relates to an electric double layer capacitor. The capacitor comprises a container type package body in which an electric double layer structure is disposed inside and a protrusion is formed on the inner side of the upper end of the sidewall; and a conductive cover which is as a cavity type cover coming in close contact with the dual layer structure to seal the body by mounting and bonding a flange formed at the edge to the plane of the protrusion. Preferably, the capacitor further comprises a sealing mold which covers the bonded part of the protrusion and the flange. The present invention provides the electric dual layer capacitor with improved productivity, airtightness, and stiffness compared to a traditional method and product.
