A bag-shaped structure excellent in vascular compressibility and creep resistance, and capable of reducing the processing cost, a blood pressure monitor cuff, and a blood pressure monitor is provided. A bag-shaped structure includes a first sheet member including a layer formed of a thermoplastic elastomer； and a second sheet member including a plurality of layers formed of a plurality of types of thermoplastic elastomers having different levels of hardness, wherein the second sheet member is joined with the first sheet member, and a layer, that is included in the plurality of layers of the second sheet member and that is in contact with a living body, has a Shore A hardness higher than a Shore A hardness of at least one of the other layers of the second sheet member.
