A fastener (20) and a cut tape (30) are provided near a first short side sealed region (12Sa) extending along one short side of a bag body (10). The fastener is provided with a first member (21) and a second member (22) which interlock with each other. The first member and the cut tape are provided to a first base member (23a), and the first base member is secured to the inner surface of a first sheet (11a) which forms the bag body. The second member is provided to a second base member (23b), and only the first short side sealed region-side end of the second base member is secured to the first base member. In a plan view of the bag body, if the area of an effective region (13) which can receive a liquid substance is A10, and the area of the region of the bag body which is located on the opposite side of the first short side sealed region-side end (13a1) of the effective region from the effective region is A11, the ratio A11/A10 is 1/7 or less.
