An ink containing device includes an ink cartridge and an adaptor. The ink cartridge includes a first main body having a first surface facing a first direction and a chamber that stores ink, an ink outlet portion disposed on the first surface of the first main body and that directs the ink from the chamber to an exterior of the first main body; and an ink detecting portion that detects an amount of the ink stored into chamber. The adapter is attachable to the ink cartridge. The adapter includes a second main body and a movable member that at with respect to the second main body.