Providing a bag-shaped structure and a method for manufacturing a bag-shaped structure, which can provide high blood pressure measurement accuracy even when the cuff width is reduced. A bag-shaped structure used in a cuff for a blood pressure monitor configured to be wrapped around a living body, inflate when a fluid is supplied to an internal space, and compress the living body includes: an inner wall portion provided on a living body side； an outer wall portion facing the inner wall portion； and a pair of side wall portions bent toward the internal space and continuous with the inner wall portion and the outer wall portion, at least part of which is formed integrally with the inner wall portion.
