Provided are a salvage container and a salvaging method capable of salvaging ammunition dumped into the sea using a simple configuration while more reliably suppressing the leakage of a chemical agent from the ammunition. A salvage container includes: a container body (30); a lid (40) that blocks an opening portion of the container body (30); a gasket (70) that is formed of a compressively deformable member and that blocks a gap between an inner side surface (33) of the container body (30) and the lid (40) from the outer side in a specific direction; and a gasket presser (50) that clamps the gasket (70) between the gasket presser (50) and the lid (40). The container body (30) includes: a lid holder (33b) that holds the lid (40) so that the lid (40) is displaced toward the outer side in the specific direction in relation to the container body (30); and a gasket presser holder (34b) that holds the gasket presser (50) so that the lid (40) is displaced toward the outer side in the specific direction in relation to the gasket presser (50) according to a decrease in the hydraulic pressure. The gasket (70) is compressively deformed by the relative displacement of the lid (40) so that the gap between the inner side surface (33) of the container body (30) and the lid (40) is hermetically sealed.