A second ink bottle is detachably attached to a bottle holder of an ink jet printer, and lower than a first ink bottle including an outflow port connected to an inflow port of the bottle holder when the ink bottle is attached to the bottle holder. The second ink bottle includes a main body having bottom and upper surfaces, in which ink is contained, a joint portion disposed on an upper portion of the main body and having an outflow port connectable to the inflow port, and a spacer detachably attached to a lower side of the main body. A height of the outflow port of the second ink bottle to a bottom surface of the spacer equals that of the outflow port of the ink bottle to a bottom surface of the first ink bottle, when the spacer is attached to the main body.