Rust-proof storage container

A rust-proof storage container comprising:

• a container body defining a storage space and having a passage or an opening between the storage space and an outer space;
• and
• a barrier material provided so as to seal the passage or the opening 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,
• wherein 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, and
• wherein 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 the outer space.