Provided is a medical instrument storage container capable not only of buffering deformations due to stresses such as vibration, impact, external pressure, etc. and absorbing such stresses to prevent the peeling of a protective film by such stresses during packing, transport, and storage, but also of preventing the peeling of the protective film during sterilization to maintain the sealed and sterilized state of the interior. A sterilized medical instrument storage container (1) equipped with: a container body (10) provided with a substantially rectangular bottom (2), a peripheral wall (3) the lower edge of which is continuous with the perimeter of the bottom (2) in all directions and which extends upward, and a rim (5) that is continuous with the upper edge of the peripheral wall (3) and extends outward, all of which are molded from resin, the container body having an opening (4) surrounded by the rim (5); medical instruments stored in the container body; and a protective film (31) to be bonded or heat-sealed on the rim (5) to cover and seal the opening (4). At least a portion of the rim (5) is curved towards the inside and the protective film (31) covers the opening (4) in a slack state.