A storage bag includes a body having a top opening, a first fitting portion and a second fitting portion disposed in the vicinity of the opening of the body, an adhesive portion disposed on an inner surface of the body in the vicinity of the first fitting portion, the adhesive portion being configured to seal the body, and a release sheet detachably adhering to the adhesive portion, the release sheet protecting the adhesive portion, and the release sheet covers at least one of the first fitting portion and the second fitting portion.