A container includes: a container body that is to be inserted into the device, and that has a port; and a pair of support members arranged so that the support members face each other across the port, that supports a cover for covering the port, the cover including: a covering portion that covers the port; a pair of supported members that are supported by the support members; and a pair of connecting portions arranged so that the connecting portions face each other, that connects the covering portion and the supported members, and at least one of the connecting members being configured so that the connecting member becomes narrow as an outside surface of the connecting member tapers towards its inside surface at an end of the container body inserted into the device.