To provide a seal member for use in a shopping bag, which does not leave waste of a release sheet when in use and can be simply applied to the shopping bag.

Rectangular flaps 34 are defined on the release sheet 13 by a U-shaped slit 23 and perforations 33 toward both ends of the sheet. By peeling the flaps 34 and 34 from an adhesive layer 12, the adhesive layer 12 is exposed at the peeled portions and thus can be applied to the shopping bag 75 across its opening. Since the flap 34 is connected to and is not separated from the other part of the release sheet 13, it is not left as waste.