An ink cartridge having a container for storing ink therein and having an ink supply port formed at a leading end side in an insertion direction of the container, a memory device disposed on a first of two opposite surfaces parallel to the insertion direction of the container, the memory device having an electrode for electrical connection to the recording device; a retaining member disposed on the first surface and located at a trailing end side relative to the memory device in the insertion direction, the retaining member serving to selectively engage with the recording device; and another retaining member disposed on the second surface and which also serves to selectively engage with the recording device.