An improvement in performance of a bag-shaped structure formed of an elastomer-made sheet can be achieved. Provided is a bag-shaped structure including one or more sheets that contain a thermoplastic elastomer and are uniform in composition, wherein the one or more sheets comprise a plurality of regions that are different in 100% Modulus. Provided also is a method of manufacturing a bag-shaped structure, including heating a region of one or more sheets that contain a thermoplastic elastomer and are uniform in composition, to a temperature that is equal to or higher than a crystallization temperature of the thermoplastic elastomer and is lower than a melting point of the thermoplastic elastomer to increase a 100% Modulus at the region relative to another region.
