The invention relates to a sealing element and a container sealed by the same. The problem to be solved is to restrain warpage of the sealing element. A sealing element (3) is provided with a base material layer (40) and a sealing layer (60) forming a bonding part for bonding a bonding object. The base material layer (40) includes a polyester film and a polyamide film, the polyamide film is laminated on the polyester film, and the hot water shrinkage of the polyamide film is larger than 1.5%. By employing the layer structure, warpage of the sealing element (3) can be restrained even if the sealing element is placed in an environment with high humidity.