PROBLEM TO BE SOLVED: To improve the protection for a content without reducing storage capacity in a bag or the like which adopts a fastener for opening and closing.SOLUTION: A storage space reinforcement structure comprises: a bag body (11) formed of a sheet member (20) for storing a long object an opening (12) for taking the long object in and out of the bag body (11) and a fastener (30) for opening and closing the opening (12). A reinforcement plate material (13) is arranged so as to cover the inside of the fastener (30). One side edge side of the reinforcement plate material (13) is connected to an opening side end edge of the sheet member (20) to which one side edge of the fastener (30) is attached. The other side edge of the reinforcement plate material (13) is formed so as to be able to abut against the opening side end edge of the sheet member (20) to which the other side edge of the fastener (30) is attached.
