Abstract: A rust-proof storage container includes a container body defining a storage space and a barrier material provided so as to seal a passage or an opening of the container body and having an area greater than a cross-sectional area of the passage or an area of the opening, the barrier material being sheet-like and having flexibility. A peripheral portion of the barrier material is fixed all around a periphery of the passage or a periphery of the opening and airtightness of the storage space is maintained by the barrier material. A center portion of the barrier material includes a first surface being a surface facing the storage space and receiving a first atmospheric pressure of the storage space and a second surface being a surface opposite the first surface and receiving a second atmospheric pressure of an outer space.