An ink cartridge is partitioned into a negative pressure generator chamber containing a negative pressure generator and a storage chamber containing an ink bag. The ink bag stores ink and supplies the ink to the negative pressure generator chamber through an ink port. The negative pressure generator absorbs and holds the ink by its capillary force, to keep pressure inside nozzles of a recording head negative to atmospheric pressure. Through a first air introduction hole, the air is introduced into the negative pressure generator chamber as the ink in the negative pressure generator chamber decreases. Through a second air introduction hole, the air is introduced into the storage chamber as the ink in the ink bag decreases. So variations in pressure inside the nozzles are suppressed, which makes ink discharge from the nozzles stable.